I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

On 7/21/2010 5:12 PM Smarty spake thus:

Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

Just a shot in the dark he any chance that flexible corrugated metal
duct, like the stuff used for old VW fan hoses, might work? Dunno what
sizes it's available in or how long it would last, but it would at least
be a lot cheaper.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

On Thu, 22 Jul 2010 00:12:47 +0000 (UTC), "Smarty"
wrote:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

A short piece of radiator hose? Takes heat, vibration and you might
find the ID you need. Auto supply store...

On 7/21/2010 7:12 PM, Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.


I install a bunch of the older 8kw units that had the Vanguard engine,
yours must have the newer Generac manufactured engine. Have you ever
seen the silicone radiator hoses installed on taxi and police car
engines? You might ask an old wrinkled up parts counter man at a real
auto parts supply house if he can find one for you.

http://www.siliconestop.com/

TDD

On 07/21/2010 08:22 PM, David Nebenzahl wrote:
On 7/21/2010 5:12 PM Smarty spake thus:

Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

Just a shot in the dark he any chance that flexible corrugated metal
duct, like the stuff used for old VW fan hoses, might work? Dunno what
sizes it's available in or how long it would last, but it would at least
be a lot cheaper.


That's what I'm thinking. Also sold at your FLAPS as "heat riser hose"
(think the hoses from the heat stove on the pass. side exhaust manifold
up to the snorkel on the air cleaner on your typical 70's-80's American
sedan.) Clamp on with regular hose clamps. Defroster hose might be
more flexible, seal better, etc. but might not be any more durable than
the original "bellows."

Alternately, a piece of radiator hose the correct diameter would
probably never, ever fail although it might not do quite as good of a
job of isolating vibrations.

You might want to look at a junkyard, because I think the air cleaner on
my old Ford pickup has a pair of flexible ducts something like that to
connect it to the throttle body ('93 with the straight six) although I
don't know the diameter off the top of my head.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On 7/21/2010 7:12 PM, Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.


Oh yea, I forgot, look at the hump hoses at the link I posted.

http://www.siliconestop.com/

http://preview.tinyurl.com/32vhs6r

TDD

On 07/21/2010 09:07 PM, The Daring Dufas wrote:
On 7/21/2010 7:12 PM, Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.


I install a bunch of the older 8kw units that had the Vanguard engine,
yours must have the newer Generac manufactured engine. Have you ever
seen the silicone radiator hoses installed on taxi and police car
engines? You might ask an old wrinkled up parts counter man at a real
auto parts supply house if he can find one for you.

http://www.siliconestop.com/

TDD


They're also sold for custom air intakes for ricers for that matter, and
that might be the best idea I've heard yet.

http://www.pegasusautoracing.com/gro...upID=TURBOHOSE

something like a "hump hose" is probably what you want, for better
vibration isolation. I don't see them that small on Pegasus' site, but
I did get a couple hits when I searched online, just nothing from a
brand I recognized. For $20 or so, it's worth a try. Just use a
*lined* hose clamp at each end; silicone hoses don't like the "teeth" on
typical worm drive hose clamps, it tears 'em up.

Pegasus *does* sell lengths of straight coolant hose in all sorts of
sizes, so that's an option too.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Smarty wrote:

I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775

Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

If you can find something in the correct size, the hose sections used to
couple turbo outputs to intercoolers and intakes would seem to be
sufficiently durable.

Since no one else has asked... Is the hose exposed to direct sunlight?
If so, can you easily remedy this? Nothing (well, relatively little)
destroys rubber as fast as the sun...

On Thu, 22 Jul 2010 00:12:47 +0000 (UTC), "Smarty"
wrote:

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

I would replace that failure-prone bellows with a length of hose that
would be available at an auto parts store. I don't believe heat is a
big concern because it is on the intake side rather than the exhaust
side.

Is there is the possibility of shortening one or both of the tubes in
question to lengthen the "flex" area? If yes, the replacement hose
would have the vibration/mis-alignment spread over a greater distance
and therefore, reduce the probability of failure.

It sounds like the engineer that designed this part must have had his
head where it didn't belong.

"Smarty" wrote in message
...
I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

Just an idea. Get a tube of silicone sealer and coat the exterior of the
hose. This will still let it flex but be sealed. WW

WW wrote:


"Smarty" wrote in message
...
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity
in this area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including
the weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to
start / run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and
only has to be the size of a pin-prick to spoil the mixture and
prevent combustion.

Generac uses a flexible coupling of this type to absorb vibration
which the engine and attached carburettor create, and dissipate it
and isolate it from the separately mounted and isolated air filter,
which sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to
have the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part
with a better life expectancy. When the first one failed during the
warranty period in the 10th month, I was told by the Generac
service technician that this was a common problem, and that Generac
has issued a newer and better bellows to fix the problem. He
assured me that I would NOT see this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was
told today by Generac that there are no new or replacement
alternatives they are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as
the current part, are there other flexible couplers which exist
which would allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1
or 2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less
vulnerable to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this
$5 rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the
usage is extremely light, nearly all of it being the weekly
check-out self-test. Unfortunately 10 months of self-test seems to
be enough to destroy this part. I am very much aware that replacing
this part on a preventative maintenance schedule every (let's say)
9 months would quite possibly solve the problem, but I am really
not interested in doing so if there is some reasonable alternative,
even if the part cost is much, much higher.

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.

Just an idea. Get a tube of silicone sealer and coat the exterior of
the hose. This will still let it flex but be sealed. WW



Thanks to everyone for your generous and extremely useful advice!

I was entirely unaware of the availability of these automotive couplers
and hoses, and will go out tomorrow to local suppliers to see what I
can find.

I am particularly tempted to go with the idea of the silicone "hump
hose" since it offers the deliberate design to flex, and is made of a
material which is vastly better than rubber in terms of high
temperature performance.

I hope to find something locally like this one:

http://www.siliconeintakes.com/produ...roducts_id=426

I also intend to ask about and see if I can find the hose types used
for risers, intercoolers, and other stressing vibration environments,
in particular if anyone has anything intended for heavy duty use. I am
not as attracted to a piece of hose since the very short connection
(approx. 2 inches total) cannot be widened. I think a hose will
transmit way more vibration to the rest of the enclosed air cleaner
assembly.

The part is not exposed to sunlight, and lies inside a cabinet housing
the generator covered on the top by a part which Generac calls the
"roof". UV bleaching and deterioration is not a concern here.

Thanks again for the great assistance here. It is very much appreciated.

Nate Nagel wrote:

On 07/21/2010 09:07 PM, The Daring Dufas wrote:
On 7/21/2010 7:12 PM, Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out
electricity in this area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years,
including the weekly exercise it does to ensure integrity, except
for one HUGE problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to
start / run.

This rubber bellows is nothing more than 2 inch long corrugated
and flexible connector which provides a flexible hose connection
between the carburettor air input and the air filter's air
output. Once it ruptures, the air/fuel ratio is grossly changed,
and the engine will neither start nor run. The rupture is not
especially visible, and only has to be the size of a pin-prick to
spoil the mixture and prevent combustion.

Generac uses a flexible coupling of this type to absorb vibration
which the engine and attached carburettor create, and dissipate
it and isolate it from the separately mounted and isolated air
filter, which sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on
this rubber part, and I have been replacing them as they fail,
only to have the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part
with a better life expectancy. When the first one failed during
the warranty period in the 10th month, I was told by the Generac
service technician that this was a common problem, and that
Generac has issued a newer and better bellows to fix the problem.
He assured me that I would NOT see this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and
was told today by Generac that there are no new or replacement
alternatives they are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can
withstand the engine compartment temperatures and vibration which
I might use instead, which would allow me merely to make a direct
2" long connection? The ID of the hose is 1.5", and should be a
pretty standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner
as the current part, are there other flexible couplers which
exist which would allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options
1 or 2 above do not exist, is there a 3rd option to treat this
rubber bellows in some manner to strengthen it and make it far
less vulnerable to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than
this $5 rubber part.

To avoid digressions, I want to point out here at the onset that
the Generac is otherwise working properly, the engine is not
vibrating excessively, the temperatures are not rising
excessively, and the usage is extremely light, nearly all of it
being the weekly check-out self-test. Unfortunately 10 months of
self-test seems to be enough to destroy this part. I am very much
aware that replacing this part on a preventative maintenance
schedule every (let's say) 9 months would quite possibly solve
the problem, but I am really not interested in doing so if there
is some reasonable alternative, even if the part cost is much,
much higher.

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.


I install a bunch of the older 8kw units that had the Vanguard
engine, yours must have the newer Generac manufactured engine. Have
you ever seen the silicone radiator hoses installed on taxi and
police car engines? You might ask an old wrinkled up parts counter
man at a real auto parts supply house if he can find one for you.

http://www.siliconestop.com/

TDD


They're also sold for custom air intakes for ricers for that matter,
and that might be the best idea I've heard yet.

http://www.pegasusautoracing.com/gro...upID=TURBOHOSE

something like a "hump hose" is probably what you want, for better
vibration isolation. I don't see them that small on Pegasus' site,
but I did get a couple hits when I searched online, just nothing from
a brand I recognized. For $20 or so, it's worth a try. Just use a
lined hose clamp at each end; silicone hoses don't like the "teeth"
on typical worm drive hose clamps, it tears 'em up.

Pegasus does sell lengths of straight coolant hose in all sorts of
sizes, so that's an option too.

nate

Thanks Nate and will definitely get lined clamps. Never knew there was
such a think until I read your reply and did some Google searching! Of
course I would have used the wrong type which apparently extrude the
silicone of the hose........

In article ,
"Smarty" wrote:

I am particularly tempted to go with the idea of the silicone "hump
hose" since it offers the deliberate design to flex, and is made of a
material which is vastly better than rubber in terms of high
temperature performance.

I hope to find something locally like this one:

http://www.siliconeintakes.com/produ...roducts_id=426

I also intend to ask about and see if I can find the hose types used
for risers, intercoolers, and other stressing vibration environments,
in particular if anyone has anything intended for heavy duty use. I am
not as attracted to a piece of hose since the very short connection
(approx. 2 inches total) cannot be widened. I think a hose will
transmit way more vibration to the rest of the enclosed air cleaner
assembly.

I'm glad you put that last sentence in there. I didn't know about hump
hoses either, but I'm skeptical that one would provide the degree of
vibration isolation that the original bellows does. I don't know what
level of vibration you're experiencing, though, so maybe the hump hose
will be fine. (I'm sure you'd rather go on replacing a $5 part every 8
months than really destroy your generator.)

Are you positive that there's no way to reconfigure that connection? It
seems that from an engineering point of view (IANAE) a nice big service
loop in the connection hose would be desirable.

On Jul 21, 7:12*pm, "Smarty" wrote:
I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775

Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

Does the air filter align itself 100% without the rubber connect
piece, does it fit properly and easily together, thinking maybe
something is wrong with its alignment that would cause alot of stress
on the rubber. Does the air filter have brackets to keep it from
moving, is it stable and attached to the motor so they vibrate
together. If something is defective and loose, out of alignment or
missing, that could account for all the failures. Have you googled for
complaints on this model. It could be a factory defect from a sloppy
build, my generac came with a bent muffler bracket and dented muffler
it was hit hard at the factory , generac sent me a new asssembly. I
think initial build quality inspections can be lacking, build quality
poor and mistakes covered up or missed by unhappy employees. I would
have a good look at a cause of failure rather than the part just being
bad. On another issue how does it hold and what is voltage under load
and at startup, mine was not adjusted right at factory but is a
portable generac not a standby unit.

On Wed, 21 Jul 2010 17:50:25 -0700, Oren wrote:

On Thu, 22 Jul 2010 00:12:47 +0000 (UTC), "Smarty"
wrote:

1. Are there any high-temperature hose materials which can withstand the
engine compartment temperatures and vibration which I might use instead,
which would allow me merely to make a direct 2" long connection? The ID
of the hose is 1.5", and should be a pretty standard, easy-to-find size.

A short piece of radiator hose? Takes heat, vibration and you might find
the ID you need. Auto supply store...

DING!

At least give this a try.

ransley wrote:

On Jul 21, 7:12*pm, "Smarty" wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity
in this area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including
the weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to
start / run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and
only has to be the size of a pin-prick to spoil the mixture and
prevent combustion.

Generac uses a flexible coupling of this type to absorb vibration
which the engine and attached carburettor create, and dissipate it
and isolate it from the separately mounted and isolated air filter,
which sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to
have the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part
with a better life expectancy. When the first one failed during the
warranty period in the 10th month, I was told by the Generac
service technician that this was a common problem, and that Generac
has issued a newer and better bellows to fix the problem. He
assured me that I would NOT see this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was
told today by Generac that there are no new or replacement
alternatives they are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775

Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as
the current part, are there other flexible couplers which exist
which would allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1
or 2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less
vulnerable to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this
$5 rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the
usage is extremely light, nearly all of it being the weekly
check-out self-test. Unfortunately 10 months of self-test seems to
be enough to destroy this part. I am very much aware that replacing
this part on a preventative maintenance schedule every (let's say)
9 months would quite possibly solve the problem, but I am really
not interested in doing so if there is some reasonable alternative,
even if the part cost is much, much higher.

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.

Does the air filter align itself 100% without the rubber connect
piece, does it fit properly and easily together, thinking maybe
something is wrong with its alignment that would cause alot of stress
on the rubber. Does the air filter have brackets to keep it from
moving, is it stable and attached to the motor so they vibrate
together. If something is defective and loose, out of alignment or
missing, that could account for all the failures. Have you googled for
complaints on this model. It could be a factory defect from a sloppy
build, my generac came with a bent muffler bracket and dented muffler
it was hit hard at the factory , generac sent me a new asssembly. I
think initial build quality inspections can be lacking, build quality
poor and mistakes covered up or missed by unhappy employees. I would
have a good look at a cause of failure rather than the part just being
bad. On another issue how does it hold and what is voltage under load
and at startup, mine was not adjusted right at factory but is a
portable generac not a standby unit.



Thanks Mark, Jeff, and Smitty for your help. As best as I can tell, the
pipes / nipples I am connecting to are aligned as well as they can be,
and that the stationary air filter assembly is pinned independently of
the vibrating engine nearby. I will take another look at it today since
I have not really been careful enough on this point, and the bottom
line truly is that the premature failures may have a lot to do with
some form of misalignment that I have overlooked.

The very short distance between the two connecting points, less than 2
inches, makes it very difficult to put merely a piece of hose in there
and expect it will take up the vibration. Even the hump connector may
not have enough damping to absorb the energy. And getting a large loop
may be a way to avoid the issue, and something I will take a look at
this afternoon also. In the final analysis, the large loop may be the
very best solution, even though it may look a bit weird. It is
certainly an easy one to try.

Other than this issue, the Generac has worked fine. Mine produces
nominal voltages under load of around 110V on each leg, and the voltage
regulator allows this to be adjusted nicely. Frequency stability is
good, and I have put a counter on it and assured myself that it remains
stable under load. The only minor issue is the waveform, which is not
especially sinusoidal. My appliances and electronics don't seem to mind
it. The unit runs both hot and noisy, but I was expecting both. I am
also not entirely happy with the transfer switch logic, which makes the
crucial decision when to throw power back to the pole when power
resumes after a blackout / failure of utility power is corrected. It
should wait a bit longer, in my opinion, and I have seen one
intermittent power interruption here causing the transfer to oscillate
more often than I would like. If I did the design, I would have chosen
at least a couple minutes for street power to return before switching
back to it and shutting down the generator.

Thanks again, and I will report back.

Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity in
this area for nearly 2 weeks.

...snip..

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

home depot has 1.5" diameter silicone water tubing. if it's not too high a
temp, that may do you. it'll be far cheaper to just buy a few feet of it and
cut off lengths a few times/year as pm.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output.


Can the air filter be moved further away? In which case a long radiator hose
with a 90 degree bend would provide the flex needed?

Or perhaps even longer and an S type hose would provide quite a bit of back
and forth movement?

Or perhaps dump that air filter and go to the automobile wrecking yard and
see what is available with the same size tube...

On Thu, 22 Jul 2010 09:42:37 -0700, Bill wrote:

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output.


Can the air filter be moved further away? In which case a long radiator
hose with a 90 degree bend would provide the flex needed?

Or perhaps even longer and an S type hose would provide quite a bit of
back and forth movement?

Or perhaps dump that air filter and go to the automobile wrecking yard
and see what is available with the same size tube...

There should be several options. I know the space is limited inside the
housing but there's got to be a better solution. Maybe look at some of
the high performance auto type filtration components. That bellow/intake
arrangement has got to have some type of pressure sensor that won't allow
the natural gas valve to open if the bellow has a leak. That would
prevent the thing from catching on fire if a leak occurred.

"Smarty" wrote in message
...
I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

One more thought. Since it is a short distance cut up a NITRAL (spelling)
glove by removing the fingers and clamping remainder in place. I use these
gloves in wood shop when using stains and thinners and they hold up fine.
The gloves are Blue in color and I buy from Harbor Freight. WW

Smarty wrote:
....
Thanks Mark, Jeff, and Smitty for your help. As best as I can tell, the
pipes / nipples I am connecting to are aligned as well as they can be,
and that the stationary air filter assembly is pinned independently of
the vibrating engine nearby. I will take another look at it today since
I have not really been careful enough on this point, and the bottom
line truly is that the premature failures may have a lot to do with
some form of misalignment that I have overlooked.

The very short distance between the two connecting points, less than 2
inches, makes it very difficult to put merely a piece of hose in there
and expect it will take up the vibration. Even the hump connector may
not have enough damping to absorb the energy. And getting a large loop
may be a way to avoid the issue, and something I will take a look at
this afternoon also. In the final analysis, the large loop may be the
very best solution, even though it may look a bit weird. It is
certainly an easy one to try.

....

Agreed it is simply a noise isolation and damper as noted.

W/O pictures hard to tell; my inclination from description and reading
w/o the hands-on would be to use the radiator hose type solution for the
connection and look at a flexible mounting for the air cleaner -- think
the exhaust system type hangers or similar -- if need more movement than
the hose itself would allow.

--

On 7/22/2010 10:08 AM WW spake thus:

One more thought. Since it is a short distance cut up a NITRAL (spelling)
glove by removing the fingers and clamping remainder in place.

Nitrile is the word you're looking for here.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

"Smarty" wrote in message
...
I personally installed a Generac natural gas stand-by generator 5 years
ago, after a freak October ice storm knocked out electricity in this
area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including the
weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to start
/ run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and only
has to be the size of a pin-prick to spoil the mixture and prevent
combustion.

Generac uses a flexible coupling of this type to absorb vibration which
the engine and attached carburettor create, and dissipate it and
isolate it from the separately mounted and isolated air filter, which
sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to have
the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part with a
better life expectancy. When the first one failed during the warranty
period in the 10th month, I was told by the Generac service technician
that this was a common problem, and that Generac has issued a newer and
better bellows to fix the problem. He assured me that I would NOT see
this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was told
today by Generac that there are no new or replacement alternatives they
are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775



Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as the
current part, are there other flexible couplers which exist which would
allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1 or
2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less vulnerable
to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this $5
rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the usage
is extremely light, nearly all of it being the weekly check-out
self-test. Unfortunately 10 months of self-test seems to be enough to
destroy this part. I am very much aware that replacing this part on a
preventative maintenance schedule every (let's say) 9 months would
quite possibly solve the problem, but I am really not interested in
doing so if there is some reasonable alternative, even if the part cost
is much, much higher.

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

Mebbe coat this rubber ditty in some kind of silicone caulk (they make a
Silicone III?) or some flexible epoxy?
There's even a kind dip for plier handles that gives a very sturdy
flexible-ish coating.
Proly some other stuff. Pliobond adhesive?

Does this bellows thing wear in one place, or does it fail anywhere? This
could affect how you choose to coat/seal this thing.

Another possibility is make some kind of adapter, and just use a tougher
flexible tubing.
--
EA

chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity
in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.

home depot has 1.5" diameter silicone water tubing. if it's not too
high a temp, that may do you. it'll be far cheaper to just buy a few
feet of it and cut off lengths a few times/year as pm.

I spent most of today searching out, buying, and trying the 'loop of
hose' method, only to learn that the bending radius for hose of this
large dimension creates a loop which just will not fit in the generator
cabinet and also will not clear the very limited adjacent carburettor
linkages, governor calibration screw, and assorted other parts. The
stronger radiator hose with internal helical wire is sturdy but very
difficult to bend to a tight loop. I did not buy a piece of silicone
tube, but I did play with some and it is also quite stiff due to the
thick walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt clamps, and
also have 3 more Generac bellows here which came from my parts
supplier. I am going to experiment further to see what remaining
options I have, including coating the bellows, installing the hump
hose, or possibly relocating things slightly. I am quite certain that
there is no way to significantly move the air cleaner assembly without
serious re-design of the internal cabinet brackets, sheet-metal, and
plastic housing, none of which I have any real desire to screw around
with. Using the current placement of everything, I am down to either a
strengthened bellows, a hump hose, or replacing the standard bellows
every 9 months or so in the preventative maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes not much
bigger than a pin hole, developing on the moving engine / carburettor
side of the connection (versus the air filter stationary side).

I would guess that the peak-to-peak vibration of the bellows creates
maybe a 3/8" to 1/2" excursion in the worn area of the rubber at the
engine rotation frequency (3600 RPM as I recall). The damn bellows has
a wall thickness of no more than about 1/16th of an inch of rubber, and
is far from being a "heavy duty" construction compared to the hoses and
hump parts I see with 4mm thickness or more.

I will update as I learn more. Thanks again!

Rad hose is good. Fermco coupler, maybe.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Oren" wrote in message
news

A short piece of radiator hose? Takes heat, vibration and you might
find the ID you need. Auto supply store...

From what I can figure, the hose doesn't have to be hose clamped down
tightly. Perhaps some silicone inside the hose (silicone spray) and
sand the fittings. Would allow the hose to slip a bit on the fittings.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Smarty" wrote in message
...

Thanks Mark, Jeff, and Smitty for your help. As best as I can tell,
the
pipes / nipples I am connecting to are aligned as well as they can be,
and that the stationary air filter assembly is pinned independently of
the vibrating engine nearby. I will take another look at it today
since
I have not really been careful enough on this point, and the bottom
line truly is that the premature failures may have a lot to do with
some form of misalignment that I have overlooked.

The very short distance between the two connecting points, less than 2
inches, makes it very difficult to put merely a piece of hose in there
and expect it will take up the vibration. Even the hump connector may
not have enough damping to absorb the energy. And getting a large loop
may be a way to avoid the issue, and something I will take a look at
this afternoon also. In the final analysis, the large loop may be the
very best solution, even though it may look a bit weird. It is
certainly an easy one to try.

Other than this issue, the Generac has worked fine. Mine produces
nominal voltages under load of around 110V on each leg, and the
voltage
regulator allows this to be adjusted nicely. Frequency stability is
good, and I have put a counter on it and assured myself that it
remains
stable under load. The only minor issue is the waveform, which is not
especially sinusoidal. My appliances and electronics don't seem to
mind
it. The unit runs both hot and noisy, but I was expecting both. I am
also not entirely happy with the transfer switch logic, which makes
the
crucial decision when to throw power back to the pole when power
resumes after a blackout / failure of utility power is corrected. It
should wait a bit longer, in my opinion, and I have seen one
intermittent power interruption here causing the transfer to oscillate
more often than I would like. If I did the design, I would have chosen
at least a couple minutes for street power to return before switching
back to it and shutting down the generator.

Thanks again, and I will report back.

Gordon Shumway posted for all of us...


On Thu, 22 Jul 2010 00:12:47 +0000 (UTC), "Smarty"
wrote:

I am open to any ideas and suggestions, and much appreciate your time
in reading this, and possibly replying. Thank you very much.

I would replace that failure-prone bellows with a length of hose that
would be available at an auto parts store. I don't believe heat is a
big concern because it is on the intake side rather than the exhaust
side.

Is there is the possibility of shortening one or both of the tubes in
question to lengthen the "flex" area? If yes, the replacement hose
would have the vibration/mis-alignment spread over a greater distance
and therefore, reduce the probability of failure.

It sounds like the engineer that designed this part must have had his
head where it didn't belong.

I agree with this. The 'flex area" is too short. Perhaps clamps on each pipe
end similar to a conduit clamp mounted to an adjustable automobile exhaust pipe
clamp may help.

Another thought is the shrouds that are used around automotive shock absorbers.

Last thought is a plumbing "Fernco fitting". Might work the best...

Lousy design IMO.

--
Tekkie Don't bother to thank me, I do this as a public service.

Smarty posted for all of us...


chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity
in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.

home depot has 1.5" diameter silicone water tubing. if it's not too
high a temp, that may do you. it'll be far cheaper to just buy a few
feet of it and cut off lengths a few times/year as pm.

I spent most of today searching out, buying, and trying the 'loop of
hose' method, only to learn that the bending radius for hose of this
large dimension creates a loop which just will not fit in the generator
cabinet and also will not clear the very limited adjacent carburettor
linkages, governor calibration screw, and assorted other parts. The
stronger radiator hose with internal helical wire is sturdy but very
difficult to bend to a tight loop. I did not buy a piece of silicone
tube, but I did play with some and it is also quite stiff due to the
thick walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt clamps, and
also have 3 more Generac bellows here which came from my parts
supplier. I am going to experiment further to see what remaining
options I have, including coating the bellows, installing the hump
hose, or possibly relocating things slightly. I am quite certain that
there is no way to significantly move the air cleaner assembly without
serious re-design of the internal cabinet brackets, sheet-metal, and
plastic housing, none of which I have any real desire to screw around
with. Using the current placement of everything, I am down to either a
strengthened bellows, a hump hose, or replacing the standard bellows
every 9 months or so in the preventative maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes not much
bigger than a pin hole, developing on the moving engine / carburettor
side of the connection (versus the air filter stationary side).

I would guess that the peak-to-peak vibration of the bellows creates
maybe a 3/8" to 1/2" excursion in the worn area of the rubber at the
engine rotation frequency (3600 RPM as I recall). The damn bellows has
a wall thickness of no more than about 1/16th of an inch of rubber, and
is far from being a "heavy duty" construction compared to the hoses and
hump parts I see with 4mm thickness or more.

I will update as I learn more. Thanks again!

See my other post but look at automotive CV joint boots.

--
Tekkie Don't bother to thank me, I do this as a public service.

On 07/22/2010 05:02 PM, Smarty wrote:
chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity
in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.

home depot has 1.5" diameter silicone water tubing. if it's not too
high a temp, that may do you. it'll be far cheaper to just buy a few
feet of it and cut off lengths a few times/year as pm.

I spent most of today searching out, buying, and trying the 'loop of
hose' method, only to learn that the bending radius for hose of this
large dimension creates a loop which just will not fit in the generator
cabinet and also will not clear the very limited adjacent carburettor
linkages, governor calibration screw, and assorted other parts. The
stronger radiator hose with internal helical wire is sturdy but very
difficult to bend to a tight loop. I did not buy a piece of silicone
tube, but I did play with some and it is also quite stiff due to the
thick walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt clamps, and
also have 3 more Generac bellows here which came from my parts
supplier. I am going to experiment further to see what remaining
options I have, including coating the bellows, installing the hump
hose, or possibly relocating things slightly. I am quite certain that
there is no way to significantly move the air cleaner assembly without
serious re-design of the internal cabinet brackets, sheet-metal, and
plastic housing, none of which I have any real desire to screw around
with. Using the current placement of everything, I am down to either a
strengthened bellows, a hump hose, or replacing the standard bellows
every 9 months or so in the preventative maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes not much
bigger than a pin hole, developing on the moving engine / carburettor
side of the connection (versus the air filter stationary side).

I would guess that the peak-to-peak vibration of the bellows creates
maybe a 3/8" to 1/2" excursion in the worn area of the rubber at the
engine rotation frequency (3600 RPM as I recall). The damn bellows has
a wall thickness of no more than about 1/16th of an inch of rubber, and
is far from being a "heavy duty" construction compared to the hoses and
hump parts I see with 4mm thickness or more.

I will update as I learn more. Thanks again!




If the carb is moving 1/2" is there a problem with the engine mounts?
Maybe even flywheel out of balance, or a misfire? That sounds like an
awful lot, a 4-cyl. or greater engine at 3600 RPM should not be moving
that much IME. Probably hard on the coupling between engine and
generator too.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On Jul 22, 4:02*pm, "Smarty" wrote:

snip

I will update as I learn more. Thanks again!

Some good ideas in all these posts, but may I suggest one more item to
look at? If the failure is due to movement between the rigid mounted
air cleaner and the engine intake, find the source of the excessive
engine movement, for example old tired gushy motor mounts. Seems to me
if the engine/intake movement is normal, then most any common
automotive hose should last for years. Good luck.

Joe

Nate Nagel wrote:

On 07/22/2010 05:02 PM, Smarty wrote:
chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by generator
5 years ago, after a freak October ice storm knocked out
electricity in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very
much.

home depot has 1.5" diameter silicone water tubing. if it's not
too high a temp, that may do you. it'll be far cheaper to just
buy a few feet of it and cut off lengths a few times/year as pm.

I spent most of today searching out, buying, and trying the 'loop of
hose' method, only to learn that the bending radius for hose of this
large dimension creates a loop which just will not fit in the
generator cabinet and also will not clear the very limited adjacent
carburettor linkages, governor calibration screw, and assorted
other parts. The stronger radiator hose with internal helical wire
is sturdy but very difficult to bend to a tight loop. I did not buy
a piece of silicone tube, but I did play with some and it is also
quite stiff due to the thick walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt clamps, and
also have 3 more Generac bellows here which came from my parts
supplier. I am going to experiment further to see what remaining
options I have, including coating the bellows, installing the hump
hose, or possibly relocating things slightly. I am quite certain
that there is no way to significantly move the air cleaner assembly
without serious re-design of the internal cabinet brackets,
sheet-metal, and plastic housing, none of which I have any real
desire to screw around with. Using the current placement of
everything, I am down to either a strengthened bellows, a hump
hose, or replacing the standard bellows every 9 months or so in the
preventative maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes not
much bigger than a pin hole, developing on the moving engine /
carburettor side of the connection (versus the air filter
stationary side).

I would guess that the peak-to-peak vibration of the bellows creates
maybe a 3/8" to 1/2" excursion in the worn area of the rubber at the
engine rotation frequency (3600 RPM as I recall). The damn bellows
has a wall thickness of no more than about 1/16th of an inch of
rubber, and is far from being a "heavy duty" construction compared
to the hoses and hump parts I see with 4mm thickness or more.

I will update as I learn more. Thanks again!




If the carb is moving 1/2" is there a problem with the engine mounts?
Maybe even flywheel out of balance, or a misfire? That sounds like
an awful lot, a 4-cyl. or greater engine at 3600 RPM should not be
moving that much IME. Probably hard on the coupling between engine
and generator too.

nate

The generator has a one cylinder, 14 HP engine. The overall excursions,
as I 'guesstimated' in my prior comment, are maybe 3/8 to 1/2 inch peak
to peak, which is basically oscillating about 3/16 to 1/4 inch in each
direction. The vibration has been about the same from original
installation to the present time, so I don't think that the motor
mounts have worn appreciably. It is possible that the mounts may have a
problem from the factory which I and the Generac technician who
serviced the unit under warranty may not have noticed.

The bellows have about a half an inch of expansion and contraction
space and would appear to be adequate to deal with the vibration in
terms of lateral 'play'. There are no specs or other adjustments,
calibrations, or measurements published for any of this.

Perhaps the one cylinder engine explains why there is more vibration
taking place than you originally expected for a 4 cylinder design?

Joe wrote:

On Jul 22, 4:02*pm, "Smarty" wrote:

snip

I will update as I learn more. Thanks again!

Some good ideas in all these posts, but may I suggest one more item to
look at? If the failure is due to movement between the rigid mounted
air cleaner and the engine intake, find the source of the excessive
engine movement, for example old tired gushy motor mounts. Seems to me
if the engine/intake movement is normal, then most any common
automotive hose should last for years. Good luck.

Joe

Joe,

I would love to pick the brains of the folks who designed this thing to
better understand the part they chose. I can surmise that the bellows
was selected to allow for a fair amount of vibration and movement
between the carburettor mounted atop the vibrating engine and the
nearby stationary air filter assembly. For reasons unknown to me, they
chose not to hang the air filter immediately above the carburettor as
was done in classical automotive designs for many years. This would
have eliminated the need for a bellows and floating connection
altogether.

I am entirely frustrated by the fact that no other Google references
show up with other people having this same problem. I would imagine
that a complaint or two, or perhaps many more would indicate that this
is indeed a design flaw rather than my own unique predicament. It tends
to give weight to the theory that something else is amiss, such as the
motor mounts. I am just not sure how much motion is typical of a single
cylinder engine, but I certainly do not recall seeing this much play in
my lawn tractor, snow blower, etc.

The bellows is made of thin rubber, no more than maybe 3mm, and
possibly thinner. It is extremely tempting to put a Fernco or other
flexible hose in the place of the bellows, but I do share the concern
that I am now transmitting much more vibration rather than dissipating
it.

I am going to call Generac tomorrow (again) and also call a local
"Master" Generac service center and see if I can glean any more
information.

I have posted a couple photos to show the inside of the Generac.

The first photo shows the overall internal layout with the bellows
highlighted by a white ellipse. The engine and carburettor are to the
left, and the enclosed air filter compartment is to the right.

The second photo is an enlarged view of the bellows area.

I did not post these earlier, since they really do not show a great
deal about the specific bellows problem area. They do reveal how tight
and space-constrained the area of the Generac is on the inside where
the defective part is situated..

http://img408.imageshack.us/img408/1...neracimage.jpg

http://img338.imageshack.us/img338/2...neracimage.jpg

Thanks once again to all!

Evan wrote:

On Jul 21, 8:12*pm, "Smarty" wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity
in this area for nearly 2 weeks.

The Generac has worked flawlessly over the last 5 years, including
the weekly exercise it does to ensure integrity, except for one HUGE
problem:

Every year or so, a $5 rubber part which Generac calls a "bellows"
ruptures without warning, leaving the generator totally unable to
start / run.

This rubber bellows is nothing more than 2 inch long corrugated and
flexible connector which provides a flexible hose connection between
the carburettor air input and the air filter's air output. Once it
ruptures, the air/fuel ratio is grossly changed, and the engine will
neither start nor run. The rupture is not especially visible, and
only has to be the size of a pin-prick to spoil the mixture and
prevent combustion.

Generac uses a flexible coupling of this type to absorb vibration
which the engine and attached carburettor create, and dissipate it
and isolate it from the separately mounted and isolated air filter,
which sits in an adjacent chamber next to the engine.

No doubt the heat and vibration of the engine do a real job on this
rubber part, and I have been replacing them as they fail, only to
have the replacement fail less than a year later.

I spoke with Genrerac's local parts distributor, and then with a
factory Generac parts manager, hoping to find a replacement part
with a better life expectancy. When the first one failed during the
warranty period in the 10th month, I was told by the Generac
service technician that this was a common problem, and that Generac
has issued a newer and better bellows to fix the problem. He
assured me that I would NOT see this happen again.

He lied, or was ill-informed...... I am now on my 4th one, and was
told today by Generac that there are no new or replacement
alternatives they are aware of.

The one and the only part they sell to do this job can be seen at:

http://www.gasoutdoor.com/details.asp?id=19775

Now that those of you with the patience to read this far know and
understand my predicament, I am posting here with the following
questions:

1. Are there any high-temperature hose materials which can withstand
the engine compartment temperatures and vibration which I might use
instead, which would allow me merely to make a direct 2" long
connection? The ID of the hose is 1.5", and should be a pretty
standard, easy-to-find size.

2. If I use a replacement coupler which has the flexibility of a
"bellows" to allow it to dissipate vibration in the same manner as
the current part, are there other flexible couplers which exist
which would allow a more permanent / durable connection?

3. If there are no superior parts to be purchased because options 1
or 2 above do not exist, is there a 3rd option to treat this rubber
bellows in some manner to strengthen it and make it far less
vulnerable to heat and vibration?

Presumably somebody must make a flexible coupler for 1.5" diameter
connections which can take the heat and vibration better than this
$5 rubber part.

To avoid digressions, I want to point out here at the onset that the
Generac is otherwise working properly, the engine is not vibrating
excessively, the temperatures are not rising excessively, and the
usage is extremely light, nearly all of it being the weekly
check-out self-test. Unfortunately 10 months of self-test seems to
be enough to destroy this part. I am very much aware that replacing
this part on a preventative maintenance schedule every (let's say)
9 months would quite possibly solve the problem, but I am really
not interested in doing so if there is some reasonable alternative,
even if the part cost is much, much higher.

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.



Ok... Some questions here...

Your generator is a little baby one compared to the 8 cylinder cat
diesel
generator sets I used to help the electrician maintain at the place I
used
to work...

(1.) How many hours of run-time do you experience between failures of
this particular part... Parts and service on generator sets are
measured
in hours of running time rather than months or years...


Approximately 1 failure every 10 running hours.





(2.) What is the recommended service interval for that particular
part in
hours? You stated that you had installed the generator after you
experienced a storm resulting in two weeks without power...

Generac has very explicit service intervals for some items, such as
spark plug, valve lash adjustment, etc. It makes no mention of this
particular part regarding preventative maintenance / replacement.


You haven't described how often the generator performs a "self-test"
and runs while switching the emergency loads to run from the
generator...

Weekly for 13 minutes per week.

(3.) If this part is causing failures for your gen set why not
replace it
on a periodic basis even though it is not yet consumed? It is a $5
part
to ensure that back up power is available... I have seen thousands of
dollars worth of parts replaced annually on two huge cat diesel gen
sets
to maintain their operational status even though the parts have not
yet
failed...


I could and I will, but since Generac never recommends it, and the
Generac service technician who replaced the first one under warranty
seemed very surprised that it had failed in less than a year, blaming
it on "a faulty bellows rubber part which has been re-designed", I can
only assume that this is NOT supposed to fail this way. It is also a
PITA to replace and would be way better if it merely held up longer.

Banks of batteries to start the generator were replaced every year in
the fall to ensure fresh good batteries would be available to crank
the
generator during the coldest of winter days even though the battery
pan was heated... These generators where integrated into the
building automation computer system so they were monitored by
many various sensors during their 20 minute exercise run time each
week down to the sine waveform the generator was putting out on each
phase and if some aspect was out of parameters the gen set could be
examined and serviced to make sure it was running in top condition
long
before it failed...

This sounds like an interesting thing to read up on in the service
manual
for your gen set to see how often your failing part should be
replaced...

As a retired electrical engineer, I have read the owner's manual as
well as the service manual cover to cover. This item is not covered.


Are you sure that there is not something unique to your generator's
installation that is causing this part to fail? Animals or insects?
Something environmental which could be weakening the rubber?

~~ Evan

A chemist friend of mine opined that a variety of synthetic rubber
products are susceptible to airborne chemicals such as lawn pesticide
spray, and can weaken as a result. A possible explanation, and one
which prompts me to consider a silicone hump hose as a replacement.
Also could justify the approach of applying a coating to the bellows by
dipping it in some magic "goo" to coat the exposed surfaces. I consider
this explanation to be a bit of a stretch, but not entirely sure.

The Daring Dufas wrote:

On 7/23/2010 12:14 AM, Smarty wrote:
Nate Nagel wrote:

On 07/22/2010 05:02 PM, Smarty wrote:
chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by
generator 5 years ago, after a freak October ice storm
knocked out electricity in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much appreciate
your time in reading this, and possibly replying. Thank you
very much.

home depot has 1.5" diameter silicone water tubing. if it's
not too high a temp, that may do you. it'll be far cheaper to
just buy a few feet of it and cut off lengths a few
times/year as pm.

I spent most of today searching out, buying, and trying the
'loop of hose' method, only to learn that the bending radius
for hose of this large dimension creates a loop which just will
not fit in the generator cabinet and also will not clear the
very limited adjacent carburettor linkages, governor
calibration screw, and assorted other parts. The stronger
radiator hose with internal helical wire is sturdy but very
difficult to bend to a tight loop. I did not buy a piece of
silicone tube, but I did play with some and it is also quite
stiff due to the thick walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt
clamps, and also have 3 more Generac bellows here which came
from my parts supplier. I am going to experiment further to see
what remaining options I have, including coating the bellows,
installing the hump hose, or possibly relocating things
slightly. I am quite certain that there is no way to
significantly move the air cleaner assembly without serious
re-design of the internal cabinet brackets, sheet-metal, and
plastic housing, none of which I have any real desire to screw
around with. Using the current placement of everything, I am
down to either a strengthened bellows, a hump hose, or
replacing the standard bellows every 9 months or so in the
preventative maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes not
much bigger than a pin hole, developing on the moving engine /
carburettor side of the connection (versus the air filter
stationary side).

I would guess that the peak-to-peak vibration of the bellows
creates maybe a 3/8" to 1/2" excursion in the worn area of the
rubber at the engine rotation frequency (3600 RPM as I recall).
The damn bellows has a wall thickness of no more than about
1/16th of an inch of rubber, and is far from being a "heavy
duty" construction compared to the hoses and hump parts I see
with 4mm thickness or more.

I will update as I learn more. Thanks again!




If the carb is moving 1/2" is there a problem with the engine
mounts? Maybe even flywheel out of balance, or a misfire? That
sounds like an awful lot, a 4-cyl. or greater engine at 3600 RPM
should not be moving that much IME. Probably hard on the
coupling between engine and generator too.

nate

The generator has a one cylinder, 14 HP engine. The overall
excursions, as I 'guesstimated' in my prior comment, are maybe 3/8
to 1/2 inch peak to peak, which is basically oscillating about 3/16
to 1/4 inch in each direction. The vibration has been about the
same from original installation to the present time, so I don't
think that the motor mounts have worn appreciably. It is possible
that the mounts may have a problem from the factory which I and the
Generac technician who serviced the unit under warranty may not
have noticed.

The bellows have about a half an inch of expansion and contraction
space and would appear to be adequate to deal with the vibration in
terms of lateral 'play'. There are no specs or other adjustments,
calibrations, or measurements published for any of this.

Perhaps the one cylinder engine explains why there is more vibration
taking place than you originally expected for a 4 cylinder design?

I confused, which model Generac standby unit has a one cylinder engine
and who manufacturers the engine. The reason I ask is that I've never
seen a Generac automatic standby gen-set with a single cylinder engine
built in the last 10 years. Back in the 1990's, I installed a number
of 8kw Generac automatic standby systems that had the Vanguard V-twin
Brigs&Stratton engine then in 1999 Generac developed their own V-twin
for the home and RV gen-set market. The last Generac system I
installed was several years ago and it had the big honkin Generac
V-twin. Somebody has even built a chopper powered by one.

http://www.youtube.com/watch?v=C6hWtuVepDU

Of course, I reread your post and it doesn't say yours is an automatic
system or the kw rating. I've serviced single cylinder automatic units
but they weren't Generac.

TDD

Thanks Nate. My Generac is described at this link:

http://reviews.northerntool.com/0394...t=rating&dir=a
sc

It is an extremely popular and highly rated unit. Home Depot and other
places sold (literally) hundreds (possibly thousands) of these in the
aftermath of the October ice storm which devastated the Northeast area
I live in a few years ago.

This one cylinder model, at 14.5 HP, makes 7KW of electricity, plenty
adequate for a smaller home.

You will see the reference to one cylinder in the link.

Smitty Two wrote:

In article ,
"Smarty" wrote:

I have posted a couple photos to show the inside of the Generac.

It sure looks like the bellows is unacceptably pre-stressed by that
other hose. I'd be re-routing that one if that's the case.

Smitty,

This certainly appears to be true, and may explain my problem entirely.
The other nearby hose actually lies well above the bellows and clears
it with no interference, but the bellows does not sit unloaded without
stress as it should, and I need to take a closer look at it. Maybe the
clamps they use are somehow deformed.

=?iso-8859-15?Q?Tekkie=AE?= wrote in
m:

Smarty posted for all of us...


chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity
in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.

home depot has 1.5" diameter silicone water tubing. if it's not too
high a temp, that may do you. it'll be far cheaper to just buy a few
feet of it and cut off lengths a few times/year as pm.

I spent most of today searching out, buying, and trying the 'loop of
hose' method, only to learn that the bending radius for hose of this
large dimension creates a loop which just will not fit in the generator
cabinet and also will not clear the very limited adjacent carburettor
linkages, governor calibration screw, and assorted other parts. The
stronger radiator hose with internal helical wire is sturdy but very
difficult to bend to a tight loop. I did not buy a piece of silicone
tube, but I did play with some and it is also quite stiff due to the
thick walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt clamps, and
also have 3 more Generac bellows here which came from my parts
supplier. I am going to experiment further to see what remaining
options I have, including coating the bellows, installing the hump
hose, or possibly relocating things slightly. I am quite certain that
there is no way to significantly move the air cleaner assembly without
serious re-design of the internal cabinet brackets, sheet-metal, and
plastic housing, none of which I have any real desire to screw around
with. Using the current placement of everything, I am down to either a
strengthened bellows, a hump hose, or replacing the standard bellows
every 9 months or so in the preventative maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes not much
bigger than a pin hole, developing on the moving engine / carburettor
side of the connection (versus the air filter stationary side).

I would guess that the peak-to-peak vibration of the bellows creates
maybe a 3/8" to 1/2" excursion in the worn area of the rubber at the
engine rotation frequency (3600 RPM as I recall). The damn bellows has
a wall thickness of no more than about 1/16th of an inch of rubber, and
is far from being a "heavy duty" construction compared to the hoses and
hump parts I see with 4mm thickness or more.

I will update as I learn more. Thanks again!

See my other post but look at automotive CV joint boots.


I wonder if the OP has written Generac to let them know about the repeated
failure of the bellows-duct?

Maybe they would like the failed parts for analysis and could come up with
a more durable part.

the CV boot idea sounds promising;a good idea.
either CV or tie rod end boot.

--
Jim Yanik
jyanik
at
localnet
dot com

Smarty wrote:

The Daring Dufas wrote:

On 7/23/2010 12:14 AM, Smarty wrote:
Nate Nagel wrote:

On 07/22/2010 05:02 PM, Smarty wrote:
chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by
generator 5 years ago, after a freak October ice storm
knocked out electricity in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much
appreciate your time in reading this, and possibly
replying. Thank you very much.

home depot has 1.5" diameter silicone water tubing. if it's
not too high a temp, that may do you. it'll be far cheaper
to just buy a few feet of it and cut off lengths a few
times/year as pm.

I spent most of today searching out, buying, and trying the
'loop of hose' method, only to learn that the bending radius
for hose of this large dimension creates a loop which just
will not fit in the generator cabinet and also will not clear
the very limited adjacent carburettor linkages, governor
calibration screw, and assorted other parts. The stronger
radiator hose with internal helical wire is sturdy but very
difficult to bend to a tight loop. I did not buy a piece of
silicone tube, but I did play with some and it is also quite
stiff due to the thick walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt
clamps, and also have 3 more Generac bellows here which came
from my parts supplier. I am going to experiment further to
see what remaining options I have, including coating the
bellows, installing the hump hose, or possibly relocating
things slightly. I am quite certain that there is no way to
significantly move the air cleaner assembly without serious
re-design of the internal cabinet brackets, sheet-metal, and
plastic housing, none of which I have any real desire to screw
around with. Using the current placement of everything, I am
down to either a strengthened bellows, a hump hose, or
replacing the standard bellows every 9 months or so in the
preventative maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes
not much bigger than a pin hole, developing on the moving
engine / carburettor side of the connection (versus the air
filter stationary side).

I would guess that the peak-to-peak vibration of the bellows
creates maybe a 3/8" to 1/2" excursion in the worn area of the
rubber at the engine rotation frequency (3600 RPM as I
recall). The damn bellows has a wall thickness of no more
than about 1/16th of an inch of rubber, and is far from being
a "heavy duty" construction compared to the hoses and hump
parts I see with 4mm thickness or more.

I will update as I learn more. Thanks again!




If the carb is moving 1/2" is there a problem with the engine
mounts? Maybe even flywheel out of balance, or a misfire? That
sounds like an awful lot, a 4-cyl. or greater engine at 3600 RPM
should not be moving that much IME. Probably hard on the
coupling between engine and generator too.

nate

The generator has a one cylinder, 14 HP engine. The overall
excursions, as I 'guesstimated' in my prior comment, are maybe 3/8
to 1/2 inch peak to peak, which is basically oscillating about
3/16 to 1/4 inch in each direction. The vibration has been about
the same from original installation to the present time, so I
don't think that the motor mounts have worn appreciably. It is
possible that the mounts may have a problem from the factory
which I and the Generac technician who serviced the unit under
warranty may not have noticed.

The bellows have about a half an inch of expansion and contraction
space and would appear to be adequate to deal with the vibration
in terms of lateral 'play'. There are no specs or other
adjustments, calibrations, or measurements published for any of
this.

Perhaps the one cylinder engine explains why there is more
vibration taking place than you originally expected for a 4
cylinder design?

I confused, which model Generac standby unit has a one cylinder
engine and who manufacturers the engine. The reason I ask is that
I've never seen a Generac automatic standby gen-set with a single
cylinder engine built in the last 10 years. Back in the 1990's, I
installed a number of 8kw Generac automatic standby systems that
had the Vanguard V-twin Brigs&Stratton engine then in 1999 Generac
developed their own V-twin for the home and RV gen-set market. The
last Generac system I installed was several years ago and it had
the big honkin Generac V-twin. Somebody has even built a chopper
powered by one.

http://www.youtube.com/watch?v=C6hWtuVepDU

Of course, I reread your post and it doesn't say yours is an
automatic system or the kw rating. I've serviced single cylinder
automatic units but they weren't Generac.

TDD

Thanks Nate. My Generac is described at this link:

http://reviews.northerntool.com/0394...ort=rating&dir
=a sc

It is an extremely popular and highly rated unit. Home Depot and other
places sold (literally) hundreds (possibly thousands) of these in the
aftermath of the October ice storm which devastated the Northeast area
I live in a few years ago.

This one cylinder model, at 14.5 HP, makes 7KW of electricity, plenty
adequate for a smaller home.

You will see the reference to one cylinder in the link.


In case you have trouble with the prior link I stated above, here is a
shorter link to the same page:

http://tinyurl.com/268lhp3

On Fri, 23 Jul 2010 05:53:32 -0500, The Daring Dufas wrote:

On 7/23/2010 12:14 AM, Smarty wrote:
Nate Nagel wrote:

On 07/22/2010 05:02 PM, Smarty wrote:
chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by generator 5
years ago, after a freak October ice storm knocked out electricity
in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much appreciate your
time in reading this, and possibly replying. Thank you very much.

home depot has 1.5" diameter silicone water tubing. if it's not too
high a temp, that may do you. it'll be far cheaper to just buy a few
feet of it and cut off lengths a few times/year as pm.

I spent most of today searching out, buying, and trying the 'loop of
hose' method, only to learn that the bending radius for hose of this
large dimension creates a loop which just will not fit in the
generator cabinet and also will not clear the very limited adjacent
carburettor linkages, governor calibration screw, and assorted other
parts. The stronger radiator hose with internal helical wire is
sturdy but very difficult to bend to a tight loop. I did not buy a
piece of silicone tube, but I did play with some and it is also quite
stiff due to the thick walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt clamps, and
also have 3 more Generac bellows here which came from my parts
supplier. I am going to experiment further to see what remaining
options I have, including coating the bellows, installing the hump
hose, or possibly relocating things slightly. I am quite certain that
there is no way to significantly move the air cleaner assembly
without serious re-design of the internal cabinet brackets,
sheet-metal, and plastic housing, none of which I have any real
desire to screw around with. Using the current placement of
everything, I am down to either a strengthened bellows, a hump hose,
or replacing the standard bellows every 9 months or so in the
preventative maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes not much
bigger than a pin hole, developing on the moving engine / carburettor
side of the connection (versus the air filter stationary side).

I would guess that the peak-to-peak vibration of the bellows creates
maybe a 3/8" to 1/2" excursion in the worn area of the rubber at the
engine rotation frequency (3600 RPM as I recall). The damn bellows
has a wall thickness of no more than about 1/16th of an inch of
rubber, and is far from being a "heavy duty" construction compared to
the hoses and hump parts I see with 4mm thickness or more.

I will update as I learn more. Thanks again!




If the carb is moving 1/2" is there a problem with the engine mounts?
Maybe even flywheel out of balance, or a misfire? That sounds like an
awful lot, a 4-cyl. or greater engine at 3600 RPM should not be moving
that much IME. Probably hard on the coupling between engine and
generator too.

nate

The generator has a one cylinder, 14 HP engine. The overall excursions,
as I 'guesstimated' in my prior comment, are maybe 3/8 to 1/2 inch peak
to peak, which is basically oscillating about 3/16 to 1/4 inch in each
direction. The vibration has been about the same from original
installation to the present time, so I don't think that the motor
mounts have worn appreciably. It is possible that the mounts may have a
problem from the factory which I and the Generac technician who
serviced the unit under warranty may not have noticed.

The bellows have about a half an inch of expansion and contraction
space and would appear to be adequate to deal with the vibration in
terms of lateral 'play'. There are no specs or other adjustments,
calibrations, or measurements published for any of this.

Perhaps the one cylinder engine explains why there is more vibration
taking place than you originally expected for a 4 cylinder design?

I confused, which model Generac standby unit has a one cylinder engine
and who manufacturers the engine. The reason I ask is that I've never
seen a Generac automatic standby gen-set with a single cylinder engine
built in the last 10 years. Back in the 1990's, I installed a number of
8kw Generac automatic standby systems that had the Vanguard V-twin
Brigs&Stratton engine then in 1999 Generac developed their own V-twin
for the home and RV gen-set market. The last Generac system I installed
was several years ago and it had the big honkin Generac V-twin. Somebody
has even built a chopper powered by one.

http://www.youtube.com/watch?v=C6hWtuVepDU

Of course, I reread your post and it doesn't say yours is an automatic
system or the kw rating. I've serviced single cylinder automatic units
but they weren't Generac.

TDD

Kohler made/makes a 15 hp single that is very well balanced and pressure
lubed. MY Deere LT155 has one in it. Bought in 2000, serviced once a year
(oil, filters) it runs like it did the day it was driven off the showroom
floor. I could easily see a derivative of the Kohler Commander single in a
standby generator. It would run very quietly though and that's one thing
the OP said his didn't do. He also said it was a 7kw generator with an
auto mains switch.

Meat Plow wrote:

On Fri, 23 Jul 2010 05:53:32 -0500, The Daring Dufas wrote:

On 7/23/2010 12:14 AM, Smarty wrote:
Nate Nagel wrote:

On 07/22/2010 05:02 PM, Smarty wrote:
chaniarts wrote:

Smarty wrote:
I personally installed a Generac natural gas stand-by
generator 5 years ago, after a freak October ice storm knocked
out electricity in this area for nearly 2 weeks.

..snip..

I am open to any ideas and suggestions, and much appreciate
your time in reading this, and possibly replying. Thank you
very much.

home depot has 1.5" diameter silicone water tubing. if it's not
too high a temp, that may do you. it'll be far cheaper to just
buy a few feet of it and cut off lengths a few times/year as pm.

I spent most of today searching out, buying, and trying the
'loop of hose' method, only to learn that the bending radius for
hose of this large dimension creates a loop which just will not
fit in the generator cabinet and also will not clear the very
limited adjacent carburettor linkages, governor calibration
screw, and assorted other parts. The stronger radiator hose with
internal helical wire is sturdy but very difficult to bend to a
tight loop. I did not buy a piece of silicone tube, but I did
play with some and it is also quite stiff due to the thick
walls, preventing a small radius bend.

I have ordered a couple hump connectors and lined T-bolt clamps,
and also have 3 more Generac bellows here which came from my
parts supplier. I am going to experiment further to see what
remaining options I have, including coating the bellows,
installing the hump hose, or possibly relocating things
slightly. I am quite certain that there is no way to
significantly move the air cleaner assembly without serious
re-design of the internal cabinet brackets, sheet-metal, and
plastic housing, none of which I have any real desire to screw
around with. Using the current placement of everything, I am
down to either a strengthened bellows, a hump hose, or replacing
the standard bellows every 9 months or so in the preventative
maintenance cycle.

The failure of the 2 bellows are fairly similar, small holes not
much bigger than a pin hole, developing on the moving engine /
carburettor side of the connection (versus the air filter
stationary side).

I would guess that the peak-to-peak vibration of the bellows
creates maybe a 3/8" to 1/2" excursion in the worn area of the
rubber at the engine rotation frequency (3600 RPM as I recall).
The damn bellows has a wall thickness of no more than about
1/16th of an inch of rubber, and is far from being a "heavy
duty" construction compared to the hoses and hump parts I see
with 4mm thickness or more.

I will update as I learn more. Thanks again!




If the carb is moving 1/2" is there a problem with the engine
mounts? Maybe even flywheel out of balance, or a misfire? That
sounds like an awful lot, a 4-cyl. or greater engine at 3600 RPM
should not be moving that much IME. Probably hard on the
coupling between engine and generator too.

nate

The generator has a one cylinder, 14 HP engine. The overall
excursions, as I 'guesstimated' in my prior comment, are maybe 3/8
to 1/2 inch peak to peak, which is basically oscillating about
3/16 to 1/4 inch in each direction. The vibration has been about
the same from original installation to the present time, so I
don't think that the motor mounts have worn appreciably. It is
possible that the mounts may have a problem from the factory which
I and the Generac technician who serviced the unit under warranty
may not have noticed.

The bellows have about a half an inch of expansion and contraction
space and would appear to be adequate to deal with the vibration in
terms of lateral 'play'. There are no specs or other adjustments,
calibrations, or measurements published for any of this.

Perhaps the one cylinder engine explains why there is more
vibration taking place than you originally expected for a 4
cylinder design?

I confused, which model Generac standby unit has a one cylinder
engine and who manufacturers the engine. The reason I ask is that
I've never seen a Generac automatic standby gen-set with a single
cylinder engine built in the last 10 years. Back in the 1990's, I
installed a number of 8kw Generac automatic standby systems that
had the Vanguard V-twin Brigs&Stratton engine then in 1999 Generac
developed their own V-twin for the home and RV gen-set market. The
last Generac system I installed was several years ago and it had
the big honkin Generac V-twin. Somebody has even built a chopper
powered by one.

http://www.youtube.com/watch?v=C6hWtuVepDU

Of course, I reread your post and it doesn't say yours is an
automatic system or the kw rating. I've serviced single cylinder
automatic units but they weren't Generac.

TDD

Kohler made/makes a 15 hp single that is very well balanced and
pressure lubed. MY Deere LT155 has one in it. Bought in 2000,
serviced once a year (oil, filters) it runs like it did the day it
was driven off the showroom floor. I could easily see a derivative of
the Kohler Commander single in a standby generator. It would run very
quietly though and that's one thing the OP said his didn't do. He
also said it was a 7kw generator with an auto mains switch.

Kohler offers a competing standby generator to my Generac, which I will
assume uses some variant of that 15 HP engine. The Generac I have here
uses a Generac-built engine.

I am linking to an exploded parts drawing from the Generac service
manual for the area I am discussing / working in. Not sure it adds
anything useful, but it illustrates how the bellows attaches to the air
filter base on one side and the engine on the other:

http://img25.imageshack.us/img25/4607/captureki.jpg