I have a leaf blower that uses a 5 hp B&S "L" head engine. The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. The carb sits on top of the fule tank.
The carb has no bowl. The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

On Apr 16, 10:30 pm, Manjo wrote:
the
engine still will not stay running for more than 30 - 40 seconds.

Got to be spark or fuel, sounds like fuel. Assuming this is a 2-
cycle, how's the fuel mix? I always like to check the simplest thing
first.

Other than that, you'll have to hold it up to the interweb so I can
hear it.
-----

- gpsman

try it with the gas cap off.

s


"Manjo" wrote in message
...
I have a leaf blower that uses a 5 hp B&S "L" head engine. The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. The carb sits on top of the fule tank.
The carb has no bowl. The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

when was the last time you saw a briggs and stratton TWO-CYCLE!?!

s


"gpsman" wrote in message
...
On Apr 16, 10:30 pm, Manjo wrote:
the
engine still will not stay running for more than 30 - 40 seconds.

Got to be spark or fuel, sounds like fuel. Assuming this is a 2-
cycle, how's the fuel mix? I always like to check the simplest thing
first.

Other than that, you'll have to hold it up to the interweb so I can
hear it.
-----

- gpsman

On Wed, 16 Apr 2008 19:30:10 -0700 (PDT), Manjo
wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. The carb sits on top of the fule tank.
The carb has no bowl. The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

Examine the spark plug or just replace it. Check for fuel /air mixture
adjustment. Make sure air filter is clean.

Compare sprak plug to this chart.

http://hawkworks.net/sparkplug-chart/

On Apr 16, 11:31*pm, gpsman wrote:
On Apr 16, 10:30 pm, Manjo wrote:

the
engine still will not stay running for more than 30 - 40 seconds.

Got to be spark or fuel, sounds like fuel. *Assuming this is a 2-
cycle, how's the fuel mix? *I always like to check the simplest thing
first.

Other than that, you'll have to hold it up to the interweb so I can
hear it.
*-----

- gpsman

gpsman,

Nope, I wish it were. It's a 4-cycle.

I have unlimited web phone. I could call you, but I think I can
describe just as well:
It starts normally and revs up fine. The governor is NOT NOT pulling
the throttle butterfly closed. After 4-5 seconds of running fine, the
rpms start to drop and within 10-15 seconds the rpms drop to zero.
When it dies, sometimes there's a small puff of exhaust out the carb,
and once I could feel a slight spray-back of fuel out of the carb.

Manjo (see other replies below)

On Apr 17, 1:00*am, "S. Barker" wrote:
try it with the gas cap off.

s

"Manjo" wrote in message

...



I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo- Hide quoted text -

- Show quoted text -

s,

I don't think it's a gas tank vacuum problem. I did remove the cap
completely and got the same symptoms with no changes (engine ran for a
little while then slowly died).

Manjo

On Apr 17, 1:04*am, Oren wrote:
On Wed, 16 Apr 2008 19:30:10 -0700 (PDT), Manjo
wrote:





I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

Examine the spark plug or just replace it. Check for fuel /air mixture
adjustment. Make sure air filter is clean.

Compare sprak plug to this chart.

http://hawkworks.net/sparkplug-chart/- Hide quoted text -

- Show quoted text -

The old spark plug was installed last fall. But I did replace the
spark plug yesterday just in case, but with no improvement.

I'll check the idle screw. There seem to be no other carb fuel
adjustment screws per the parts list and B&S repair manual.

Manjo

On Apr 17, 1:04*am, Oren wrote:
On Wed, 16 Apr 2008 19:30:10 -0700 (PDT), Manjo
wrote:





I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

Examine the spark plug or just replace it. Check for fuel /air mixture
adjustment. Make sure air filter is clean.

Compare sprak plug to this chart.

http://hawkworks.net/sparkplug-chart/- Hide quoted text -

- Show quoted text -

Sorry, forgot to reply to additinal tips:

I get the same engine dying with and without the air filter in place.

As for spark plug color, the new spark plug looks a bit oil covered,
but I'm guessing the shiny look is more form unburnt gas, but I'm not
sure.

Manjo

Manjo wrote:
I have a leaf blower that uses a 5 hp B&S "L" head engine. The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. The carb sits on top of the fule tank.
The carb has no bowl. The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo


Any chance the choke butterfly is oozing closed somehow?

Last year I had a similar frustrating problem with the vertical shaft
Tecumseh on my rotary mower. If I pushed down on the handle to raise the
front of the mower the engine would slow down noticably, but not stop.

I tried all the usuals, including draining and cleaning the fuel tank
and disassembling, cleaning and reassembling the carb with new caskets, etc.

Nothing changed, the engine still slowed down when tilted slightly back.
Not wanting to make a PhD thesis out of it I just bought a new carb
online, installed it and "Bob's yer uncle", problem gone.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

"Manjo" wrote in message
...
I have a leaf blower that uses a 5 hp B&S "L" head engine. The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. The carb sits on top of the fule tank.
The carb has no bowl. The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo
The symptoms sound consistent with fuel starvation. If so, you should be
able to get it to run a bit longer by partially closing the choke or by
squirting a little gasoline into the intake as it starts to die. If that
does not help, you likely have a temperature related ignition failure. That
could be caused by a control module, ignition coil or condenser.

If it is fuel related, first be sure you have good fresh gasoline. Otherwise
there is almost certainly something wrong with the carburetor. Use a
carburetor cleaning spray to be certain that all passages are clean and be
sure you have all the parts correctly installed. If it has one, carefully
check the inlet filter screen at the bottom of the carburetor. A partially
clogged filter could cause it to start after sitting a while but not allow
enough fuel to pass to keep it running.

Don Young

On Thu, 17 Apr 2008 20:58:56 -0500, "Don Young"
wrote:


"Manjo" wrote in message
...
I have a leaf blower that uses a 5 hp B&S "L" head engine. The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. The carb sits on top of the fule tank.
The carb has no bowl. The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo
The symptoms sound consistent with fuel starvation. If so, you should be
able to get it to run a bit longer by partially closing the choke or by
squirting a little gasoline into the intake as it starts to die. If that
does not help, you likely have a temperature related ignition failure. That
could be caused by a control module, ignition coil or condenser.

If it is fuel related, first be sure you have good fresh gasoline. Otherwise
there is almost certainly something wrong with the carburetor. Use a
carburetor cleaning spray to be certain that all passages are clean and be
sure you have all the parts correctly installed. If it has one, carefully
check the inlet filter screen at the bottom of the carburetor. A partially
clogged filter could cause it to start after sitting a while but not allow
enough fuel to pass to keep it running.

Don Young


It sounds fuel starved to me. Checking the spark with the plug out and
grounded to the head would tell if there is enough spark (bright blue,
snappy and not a weak yellow). Then I would use a carb /starting
fluid.

As the engine is about to die spray into the carb throat. If the
engine picks up pep, runs higher rpm....check the carb.

*ONE* thing I would be sure to check is the gas line. Look for small
cracks and /or replace.

Next is! How is the fuel filter?

On Apr 18, 1:18*am, Oren wrote:
On Thu, 17 Apr 2008 20:58:56 -0500, "Don Young"
wrote:







"Manjo" wrote in message
...
I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo
The symptoms sound consistent with fuel starvation. If so, you should be
able to get it to run a bit longer by partially closing the choke or by
squirting a little gasoline into the intake as it starts to die. If that
does not help, you likely have a temperature related ignition failure. That
could be caused by a control module, ignition coil or condenser.

If it is fuel related, first be sure you have good fresh gasoline. Otherwise
there is almost certainly something wrong with the carburetor. Use a
carburetor cleaning spray to be certain that all passages are clean and be
sure you have all the parts correctly installed. If it has one, carefully
check the inlet filter screen at the bottom of the carburetor. A partially
clogged filter could cause it to start after sitting a while but not allow
enough fuel to pass to keep it running.

Don Young

It sounds fuel starved to me. Checking the spark with the plug out and
grounded to the head would tell if there is enough spark (bright blue,
snappy and not a weak yellow). Then I would use a carb /starting
fluid.

As the engine is about to die spray into the carb throat. If the
engine picks up pep, runs higher rpm....check the carb.

*ONE* thing I would be sure to check is the gas line. Look for small
cracks and /or replace.

Next is! How is the fuel filter?- Hide quoted text -

- Show quoted text -

GROUP REPLY (Don, Jeff, jp):

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. Keeping the choke on full
kills the engine faster.

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line. The carb fits directly on top of and is bolted
to the fuel tank and then the carb is bolted to the engine. There's
no fuel line. There's a nylon or plastic feed tube from the carb into
the tank. There's also a small reservoir at the top of the tank that
looks like a idle feed tube with an intake jet at the bottom that I
believe feeds the carb's idle circuit. I blew compressed air through
all the carb circuits yesterday, but TODAY I will also spray
Berryman’s carb cleaner through all the circuits before putting
everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. The butterfly arm sits in a slotted nylon detent that
holds the arm in place. As far as I can tell, the butterfly is
staying firmly in place. I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). But even constantly spraying starter fluid into the carb
won’t keep it running. I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. Please keep them coming if
you see I'm missing anything.

Manjo

On Apr 16, 10:30*pm, Manjo wrote:
I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. There's no fuel line. There's a nylon or plastic feed
tube from the carb into the tank. There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. The butterfly arm sits in a slotted nylon detent that
holds the arm in place. As far as I can tell, the butterfly is
staying firmly in place. I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). But even constantly spraying starter fluid into the carb
won’t keep it running. I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. Please keep them coming if
you see I'm missing anything.

Manjo

A bad valve would not cause this symptom.

s

wrote in message
...
had to do a valve job on mine when it did that.lucas

----------------------------------------------------------------
http://www.minibite.com/america/malone.htm

"S. Barker" wrote:

when was the last time you saw a briggs and stratton TWO-CYCLE!?!

Although the original poster's engine is a 4 cycle, B&S certainly has made
two cycle engines, and I believe they still do, at least for some snow
applications.

http://www.briggsandstratton.com/ima...c_l_800100.jpg

Well then i stand corrected. I had no idea they'd try that market. I guess
they figgered they failed the four stroke test. (they USED to make the best
4 stroke on the market, now they're junk)

s


"Jeff" wrote in message ...


"S. Barker" wrote:

when was the last time you saw a briggs and stratton TWO-CYCLE!?!

Although the original poster's engine is a 4 cycle, B&S certainly has made
two cycle engines, and I believe they still do, at least for some snow
applications.

http://www.briggsandstratton.com/ima...c_l_800100.jpg

On Apr 18, 12:22*pm, Manjo wrote:
On Apr 16, 10:30*pm, Manjo wrote:





I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. *Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. *I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. *I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. *The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. *Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. *I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. *There's no fuel line. *There's a nylon or plastic feed
tube from the carb into the tank. *There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. *I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. *The butterfly arm sits in a slotted nylon detent that
holds the arm in place. *As far as I can tell, the butterfly is
staying firmly in place. *I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). *But even constantly spraying starter fluid into the carb
won’t keep it running. *I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. *If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. *Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. Does anyone know what voltage the
magneto is creating? Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

On Apr 16, 9:30*pm, Manjo wrote:
I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

It probably has an electronic ignition mobule, see if it gets spark
just after dying, if its very old with points maybe a capacitor is bad

On Apr 18, 5:04 pm, Manjo wrote:
On Apr 18, 12:22 pm, Manjo wrote:



On Apr 16, 10:30 pm, Manjo wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. The carb sits on top of the fule tank.
The carb has no bowl. The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. There's no fuel line. There's a nylon or plastic feed
tube from the carb into the tank. There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. The butterfly arm sits in a slotted nylon detent that
holds the arm in place. As far as I can tell, the butterfly is
staying firmly in place. I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). But even constantly spraying starter fluid into the carb
won’t keep it running. I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. Does anyone know what voltage the
magneto is creating? Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

When you had the carb apart to change the diaphragm and clean the pick-
up tube...did you shoot carb cleaner thru the jets to see if they are
clear?

On Fri, 18 Apr 2008 12:49:21 -0400, wrote:

had to do a valve job on mine when it did that.lucas

Like killing a gnat with a hammer :-)

On Fri, 18 Apr 2008 15:04:18 -0700 (PDT), Manjo
wrote:

On Apr 18, 12:22*pm, Manjo wrote:
On Apr 16, 10:30*pm, Manjo wrote:





I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. *Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. *I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. *I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. *The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. *Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. *I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. *There's no fuel line. *There's a nylon or plastic feed
tube from the carb into the tank. *There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. *I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. *The butterfly arm sits in a slotted nylon detent that
holds the arm in place. *As far as I can tell, the butterfly is
staying firmly in place. *I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). *But even constantly spraying starter fluid into the carb
won’t keep it running. *I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. *If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. *Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. Does anyone know what voltage the
magneto is creating? Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

....(magneto) results in up to 10,000 V or more at the spark plug.

read this page..(Testing the magneto)

http://www.repairfaq.org/samnew/lmfaq/lmtstmgto.htm

On Apr 18, 6:22 pm, wrote:
On Apr 18, 5:04 pm, Manjo wrote:



On Apr 18, 12:22 pm, Manjo wrote:

On Apr 16, 10:30 pm, Manjo wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. The carb sits on top of the fule tank.
The carb has no bowl. The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. There's no fuel line. There's a nylon or plastic feed
tube from the carb into the tank. There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. The butterfly arm sits in a slotted nylon detent that
holds the arm in place. As far as I can tell, the butterfly is
staying firmly in place. I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). But even constantly spraying starter fluid into the carb
won’t keep it running. I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. Does anyone know what voltage the
magneto is creating? Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

When you had the carb apart to change the diaphragm and clean the pick-
up tube...did you shoot carb cleaner thru the jets to see if they are
clear?

My thought on the mag being bad...it would take minutes not seconds
for it to thermally fail.

On Apr 18, 6:18*pm, ransley wrote:
On Apr 16, 9:30*pm, Manjo wrote:





I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

It probably has an electronic ignition mobule, see if it gets spark
just after dying, if its very old with points maybe a capacitor is bad- Hide quoted text -

- Show quoted text -

THe engine is about 10 years old. Here's a link I created to the
parts manual pdf file.

http://home.comcast.net/~manjo1111/B...LIST%20old.pdf

Page 7 has an exploded parts diagram and lists all the "electronics".
I don't know or understand magneto systems very well other than they
are designed to be create a spark without the need for a battery or
alternator. I've looked on the engine and in the parts list and all I
see are the magneto assembly (windings block and spark plug wire)
bolted to the engine block, and what looks like a set of aluminum(?)
finds on the rotor that interrupt the creation of current in order to
create a spark at the plug. Manjo

On Apr 18, 7:22*pm, wrote:
On Apr 18, 5:04 pm, Manjo wrote:





On Apr 18, 12:22 pm, Manjo wrote:

On Apr 16, 10:30 pm, Manjo wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank..
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. *Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. *I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. *I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. *The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. *Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. *I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. *There's no fuel line. *There's a nylon or plastic feed
tube from the carb into the tank. *There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. *I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. *The butterfly arm sits in a slotted nylon detent that
holds the arm in place. *As far as I can tell, the butterfly is
staying firmly in place. *I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). *But even constantly spraying starter fluid into the carb
won’t keep it running. *I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. *If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. *Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. *The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. *I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. *I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? *My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. *Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. *Does anyone know what voltage the
magneto is creating? *Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

When you had the carb apart to change the diaphragm and clean the pick-
up tube...did you shoot carb cleaner thru the jets to see if they are
clear?- Hide quoted text -

- Show quoted text -

Yes. I sprayed Berrymans B-12 carb cleaner into all carb circuits I
could find including removing a small idle circuit screw and spraying
fluid in there too. I looked for and saw spray fluid drip out the
other end of the ciruits. I then blew compressed air into each
circuit and felt fluid and then air come out the other end of the
circuit.

For what it's worth, there are only four (4) circuits I could locate:
main pick-up tube circuit from the gas tank into the main carnb
venturi; a shorter pick-up carb arm at the bottom with a jet fed from
a small "cup" at the top of the gas tank; the idle circuit adjustment
screw hole at the side; and what looks like an EPA crankcase gases
recirculation port from a cover over the valves feeding back into and
just above the choke butterfly valve. Here's a link I created to
the Parts List pdf. The carb parts are shown and listed on Page 4.
http://home.comcast.net/~manjo1111/B...LIST%20old.pdf

Manjo

On Apr 18, 9:44*pm, Oren wrote:
On Fri, 18 Apr 2008 15:04:18 -0700 (PDT), Manjo
wrote:





On Apr 18, 12:22*pm, Manjo wrote:
On Apr 16, 10:30*pm, Manjo wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. *Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. *I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. *I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. *The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. *Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. *I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. *There's no fuel line. *There's a nylon or plastic feed
tube from the carb into the tank. *There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. *I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. *The butterfly arm sits in a slotted nylon detent that
holds the arm in place. *As far as I can tell, the butterfly is
staying firmly in place. *I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). *But even constantly spraying starter fluid into the carb
won’t keep it running. *I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. *If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. *Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. *The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. *I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. *I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? *My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. *Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. *Does anyone know what voltage the
magneto is creating? *Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

...(magneto) results in up to 10,000 V or more at the spark plug.

read this page..(Testing the magneto)

http://www.repairfaq.org/samnew/lmfaq/lmtstmgto.htm- Hide quoted text -

- Show quoted text -

Great page. I looked at my multimeter and it can only handle up to
1,000 DCV. 10,000 DCV would blow mine up.

Manjo

On Apr 19, 7:59*am, wrote:
On Apr 18, 6:22 pm, wrote:





On Apr 18, 5:04 pm, Manjo wrote:

On Apr 18, 12:22 pm, Manjo wrote:

On Apr 16, 10:30 pm, Manjo wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. *Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. *I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. *I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. *The funnel/filter were feeding into a clean gas container.. I
did this several times and I DID get A LOT more debris out of the
tank. *Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. *I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. *There's no fuel line. *There's a nylon or plastic feed
tube from the carb into the tank. *There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. *I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. *The butterfly arm sits in a slotted nylon detent that
holds the arm in place. *As far as I can tell, the butterfly is
staying firmly in place. *I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). *But even constantly spraying starter fluid into the carb
won’t keep it running. *I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. *If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. *Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. *The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. *I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. *I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? *My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. *Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. *Does anyone know what voltage the
magneto is creating? *Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

When you had the carb apart to change the diaphragm and clean the pick-
up tube...did you shoot carb cleaner thru the jets to see if they are
clear?

My thought on the mag being bad...it would take minutes not seconds
for it to thermally fail.- Hide quoted text -

- Show quoted text -

I don't know anything about magnetos. I have to ask why would it take
minutes? Would it take that long for a winding to heat up and
separate (if that's possible)? I get a 2,500 ohm reading through the
spark plug cap to the body of the magneto. I did visually check the
connections and there are only a couple and they seemed in place when
I getnly pushed them with a screw driver tip.

Manjo

Manjo wrote:
I have a leaf blower that uses a 5 hp B&S "L" head engine. ...
....
The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.


I've not read the rest of the thread but noted you were apparently still
searching --

Anybody suggested checking the exhaust screen (I'm assuming it has one)
for C deposits? Sounds like it could be clogged w/ buildup which will
cause such symptoms...

--

On Sat, 19 Apr 2008 07:33:17 -0700 (PDT), Manjo
wrote:

On Apr 18, 9:44*pm, Oren wrote:
On Fri, 18 Apr 2008 15:04:18 -0700 (PDT), Manjo
wrote:





On Apr 18, 12:22*pm, Manjo wrote:
On Apr 16, 10:30*pm, Manjo wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. *Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. *I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. *I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. *The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. *Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. *I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. *There's no fuel line. *There's a nylon or plastic feed
tube from the carb into the tank. *There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. *I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. *The butterfly arm sits in a slotted nylon detent that
holds the arm in place. *As far as I can tell, the butterfly is
staying firmly in place. *I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). *But even constantly spraying starter fluid into the carb
won’t keep it running. *I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. *If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. *Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. *The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. *I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. *I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? *My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. *Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. *Does anyone know what voltage the
magneto is creating? *Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

...(magneto) results in up to 10,000 V or more at the spark plug.

read this page..(Testing the magneto)

http://www.repairfaq.org/samnew/lmfaq/lmtstmgto.htm- Hide quoted text -

- Show quoted text -

Great page. I looked at my multimeter and it can only handle up to
1,000 DCV. 10,000 DCV would blow mine up.

Manjo

Do a "shade tree mechanic" (G) test. Pull the plug, re-attach the wire
on the plug and lay the plug on a good ground (scratch the paint) of
metal. Pull the start rope and watch the spark. You want to see a
bright blue spark and hear it snap.

(The other method is to hold the plug wire terminal in your hand give
'er a yank on the rope BTDT.

The flywheel has two magnets inside (not shown in your .pdf file).
They can become corroded and a simply cleaning with a fine sand paper
can clean them to a shine.

Magnetos do go bad, but very seldom in my experience.

Look on the last page at part #147 (Seal Needle Valve) and part #118
(adjustment screw), If one or both are damaged, you'll not get the
proper adjustment.

Examine the tip of the screw for damage or wear. Sometimes they bend
the tip of the screw if the tighten them down to far into the seat.

I'm throwing things out there, because I like/want to avoid pulling
the flywheel.

Now, have you hit anything last fall with the mower? The flywheel has
a shear pin. It can be a small fracture, but the timing is off on the
magneto...just a bit.

On Sat, 19 Apr 2008 10:00:24 -0500, dpb wrote:

Manjo wrote:
I have a leaf blower that uses a 5 hp B&S "L" head engine. ...
...
The leaf blower was starting to run poorly last fall. This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.


I've not read the rest of the thread but noted you were apparently still
searching --

Anybody suggested checking the exhaust screen (I'm assuming it has one)
for C deposits? Sounds like it could be clogged w/ buildup which will
cause such symptoms...

How about checking around the head gasket for leaks. I had a lawnmower
engine that exhibited a similar problem.

On Apr 20, 7:27*am, Gary Dyrkacz.
wrote:
On Sat, 19 Apr 2008 10:00:24 -0500, dpb wrote:
Manjo wrote:
I have a leaf blower that uses a 5 hp B&S "L" head engine. *...
...
The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

I've not read the rest of the thread but noted you were apparently still
searching --

Anybody suggested checking the exhaust screen (I'm assuming it has one)
for C deposits? *Sounds like it could be clogged w/ buildup which will
cause such symptoms...

How about checking around the head gasket for leaks. I had a lawnmower
engine that exhibited a similar problem.- Hide quoted text -

- Show quoted text -

I know it doesn't do much good, but I did do a visual check of the
head gasket edges. Nothing unusual, but I'll check it with some sudsy
water today. I lent out my leak down tester (I hope to get back soon)
so I had to use a standard cylinder compression tester. I got
consistent readings of 74 psi with a warm (not hot) engine. I think
this is a good reading since it's a small cylinder, unlike an auto
engine cylinder. Manjo

On Apr 19, 11:00*am, dpb wrote:
Manjo wrote:
I have a leaf blower that uses a 5 hp B&S "L" head engine. *...
...
The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

I've not read the rest of the thread but noted you were apparently still
searching --

Anybody suggested checking the exhaust screen (I'm assuming it has one)
for C deposits? *Sounds like it could be clogged w/ buildup which will
cause such symptoms...

--- Hide quoted text -

- Show quoted text -

The exhaust has not been checked. I did put my hand near the exhaust
canister and I could feel puffs of air as the engine ran at normal
rpm. But now that you mention this, the air pressure felt a little
low or soft. I'll pull the can and check it today. Manjo

On Apr 19, 10:40*pm, Oren wrote:
On Sat, 19 Apr 2008 07:33:17 -0700 (PDT), Manjo
wrote:





On Apr 18, 9:44*pm, Oren wrote:
On Fri, 18 Apr 2008 15:04:18 -0700 (PDT), Manjo
wrote:

On Apr 18, 12:22*pm, Manjo wrote:
On Apr 16, 10:30*pm, Manjo wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. *Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. *I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. *I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. *The funnel/filter were feeding into a clean gas container.. I
did this several times and I DID get A LOT more debris out of the
tank. *Most of the pieces were about 1/64th to 1/32nd of an inch.
Some stuff was black and other pieces were sand in color. *I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. *There's no fuel line. *There's a nylon or plastic feed
tube from the carb into the tank. *There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. *I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. *The butterfly arm sits in a slotted nylon detent that
holds the arm in place. *As far as I can tell, the butterfly is
staying firmly in place. *I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). *But even constantly spraying starter fluid into the carb
won’t keep it running. *I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. *If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. *Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. *The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. *I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. *I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? *My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. *Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. *Does anyone know what voltage the
magneto is creating? *Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

...(magneto) results in up to 10,000 V or more at the spark plug.

read this page..(Testing the magneto)

http://www.repairfaq.org/samnew/lmfa...tmgto.htm-Hide quoted text -

- Show quoted text -

Great page. *I looked at my multimeter and it can only handle up to
1,000 DCV. *10,000 DCV would blow mine up.

Manjo

Do a "shade tree mechanic" (G) test. Pull the plug, re-attach the wire
on the plug *and *lay the plug on a good ground (scratch the paint) of
metal. Pull the start rope and watch the spark. You want to see a
bright blue spark and hear it snap.

(The other method is to hold the plug wire terminal in your hand give
'er a yank on the rope BTDT.

The flywheel has two magnets inside (not shown in your .pdf file).
They can become corroded and a simply cleaning with a fine sand paper
can clean them to a shine.

Magnetos do go bad, but very seldom in my experience.

Look on the last page at part #147 (Seal Needle Valve) and part #118
(adjustment screw), If one or both are damaged, you'll not get the
proper adjustment.

Examine the tip of the screw for damage or wear. Sometimes they bend
the tip of the screw if the tighten them down to far into the seat.

I'm throwing things out there, because I like/want to avoid pulling
the flywheel.

Now, have you hit anything last fall with the mower? The flywheel has
a shear pin. It can be a small fracture, but the timing is off on the
magneto...just a bit.- Hide quoted text -

- Show quoted text -


Good idea to clean the magneto. I've been hesitant to remove the
magneto since it seems to be a pretty close fit to the rotor and I
didn't want to introduce another problem, but it's time now. The
rotor itself has some light rust that I'll sand lightly, too.

I did a similar spark plug test a few days ago. I left the spark plug
in the engine port and put another spark plug in the cap and held it
to the top of the first and I was able to start the engine. Although
it ran a little slower rpm-wise, the engine functioned close to normal
and I could see a spark across the hand-help plug gap that looked
good. As the engine slowed down, there was more yellow coloration to
the spark and then the engine died. I will try this and your test
again just to be sure I’m getting a decent spark after I clean the
magneto and rotor.

I haven't chased the valve seat, but I did spray it with carb cleaner
and blew it out with compressed air. I checked the idle adjustment
needle tip and it looked good: it was straight and did not have any
apparent wear or damage to the tip.

I'll check all these things today.

Manjo

On Apr 20, 7:54*am, Manjo wrote:
On Apr 19, 10:40*pm, Oren wrote:





On Sat, 19 Apr 2008 07:33:17 -0700 (PDT), Manjo
wrote:

On Apr 18, 9:44*pm, Oren wrote:
On Fri, 18 Apr 2008 15:04:18 -0700 (PDT), Manjo
wrote:

On Apr 18, 12:22*pm, Manjo wrote:
On Apr 16, 10:30*pm, Manjo wrote:

I have a leaf blower that uses a 5 hp B&S "L" head engine. *The carb
is pretty simple with a choke butterfly, throttle butterfly, and
rubber diaphragm fuel pump. *The carb sits on top of the fule tank.
The carb has no bowl. *The governor linakges are clean and the
governor appears to be working fine.

The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds..

Thanks in advance for any tips, suggestions, or coments.

Manjo

The engine starts, revs properly and then dies with the choke
partially or fully OFF about the same time. *Keeping the choke on full
kills the engine faster.

GROUP REPLY TO Don, Jeff, jp (might be a duplicate post)

A couple of days ago when I started working on this problem, the fuel
intake screen at the bottom of the intake tube in the gas tank had a
lot of junk in it. *I pulled the intake tube off the brass intake tube
and sprayed both with non-residue brake cleaner fluid and blew air
through the tubes both ways to clean them out.

Yesterday, I DID take the gas tank completely off the engine and used
filtered gasoline to flush the tank. *I swirled the gas in the tank
and then poured the gas from the tank into a funnel lined with a paper
filter. *The funnel/filter were feeding into a clean gas container. I
did this several times and I DID get A LOT more debris out of the
tank. *Most of the pieces were about 1/64th to 1/32nd of an inch..
Some stuff was black and other pieces were sand in color. *I’m
wondering if stuff is getting TEMPORARILY sucked up against the intake
screen killing the engine, then the debris drops back on to the bottom
of the tank when the engine dies???

There is no fuel line and no inline fuel filter other than the wire
screeen at the bottom of the intake tube. The carb fits directly on
top of and is bolted to the fuel tank and then the carb is bolted to
the engine. *There's no fuel line. *There's a nylon or plastic feed
tube from the carb into the tank. *There's also a small reservoir at
the top of the tank that looks like a idle feed tube with an intake
jet at the bottom that I believe feeds the carb's idle circuit. *I
blew compressed air through all the carb circuits yesterday, but TODAY
I will also spray Berryman’s carb cleaner through all the circuits
before putting everything back together.

I have the air filter off the carb and can see the entire choke
butterfly. *The butterfly arm sits in a slotted nylon detent that
holds the arm in place. *As far as I can tell, the butterfly is
staying firmly in place. *I don't have a tilting problem since the
carb has no carb bowl or float.

I have gotten the engine to run a second or two longer each time I
spray engine-starting fuel into the carb intake (at the choke
butterfly). *But even constantly spraying starter fluid into the carb
won’t keep it running. *I have not tried spraying gas into the carb
because I'm assuming the starter fluid is more condensed and more
volatile than regular gas.

I hope it is a fuel starvation problem and this will fix the dying
problem. *If it doesn't, then I'm going to replace the magneto.

Thanks for all the great tips and replies. *Please keep them coming if
you see I'm missing anything.

Manjo- Hide quoted text -

- Show quoted text -

Got it all back together and it ran just a bit better. *The engine
still runs fine for a few seconds and then start the same decline
until it stops.

I watched everything and it all seemed to function correctly. *I then
tried pressing down and twisting the spark plug cap and the engine
"seemed" to run a little longer at proper rpm, but it still died. *I
crimped the spark plug c0onnector and it ran a few seconds more, but
still died.

My current theory is there's a magneto or spark plug cable problem.
I'm going to try crimping the spark plug cap tighter and if that
helps, but doesn’t solve the problem, I'll take the magneto off the
engine and check it visually.

Does anyone know how to test a magneto? *My magneto is behind the pull
starter and cover combination, and to gain access to the magneto
requires removing the cover, but no way to hand starts the engine with
the recoil starter off the engine. *Right now, when I do an ohms test,
I get 2,500 ohms with one probe on the spark plug cap and the other
probe against the magneto body. *Does anyone know what voltage the
magneto is creating? *Can a standard voltmeter be set-up between the
spark plug and spark plug cap for a reading, or will the magneto blow
out the meter?

TIA for everyone's help.

Manjo

...(magneto) results in up to 10,000 V or more at the spark plug.

read this page..(Testing the magneto)

http://www.repairfaq.org/samnew/lmfa...htm-Hidequoted text -

- Show quoted text -

Great page. *I looked at my multimeter and it can only handle up to
1,000 DCV. *10,000 DCV would blow mine up.

Manjo

Do a "shade tree mechanic" (G) test. Pull the plug, re-attach the wire
on the plug *and *lay the plug on a good ground (scratch the paint) of
metal. Pull the start rope and watch the spark. You want to see a
bright blue spark and hear it snap.

(The other method is to hold the plug wire terminal in your hand give
'er a yank on the rope BTDT.

The flywheel has two magnets inside (not shown in your .pdf file).
They can become corroded and a simply cleaning with a fine sand paper
can clean them to a shine.

Magnetos do go bad, but very seldom in my experience.

Look on the last page at part #147 (Seal Needle Valve) and part #118
(adjustment screw), If one or both are damaged, you'll not get the
proper adjustment.

Examine the tip of the screw for damage or wear. Sometimes they bend
the tip of the screw if the tighten them down to far into the seat.

I'm throwing things out there, because I like/want to avoid pulling
the flywheel.

Now, have you hit anything last fall with the mower? The flywheel has
a shear pin. It can be a small fracture, but the timing is off on the
magneto...just a bit.- Hide quoted text -

- Show quoted text -

Good idea to clean the magneto. *I've been hesitant to remove the
magneto since it seems to be a pretty close fit to the rotor and I
didn't want to introduce another problem, but it's time now. *The
rotor itself has some light rust that I'll sand lightly, too.

I did a similar spark plug test a few days ago. *I left the spark plug
in the engine port and put another spark plug in the cap and held it
to the top of the first and I was able to start the engine. *Although
it ran a little slower rpm-wise, the engine functioned close to normal
and I could see a spark across the hand-help plug gap that looked
good. *As the engine slowed down, there was more yellow coloration to
the spark and then the engine died. *I will try this and your test
again just to be sure I’m getting a decent spark after I clean the
magneto and rotor.

I haven't chased the valve seat, but I did spray it with carb cleaner
and blew it out with compressed air. *I checked the idle adjustment
needle tip and it looked good: *it was straight and did not have any
apparent wear or damage to the tip.

I'll check all these things today.

Manjo- Hide quoted text -

- Show quoted text -

If spark is yellow its weak, it should be white to blue white,

Here's a wild thought; I read that it's a leaf blower. Is there a belt
drive in it? Was thinking of a way to power the engine using a drive to spin
the motor - with the plug out and grounded. Long enough to see if the coil
overheats and breaks down and loses spark. That would at least remove one of
the variables. Having gone through a series of question with a 8 hp briggs L
head (finally found an intermittent intake valve) that caused me some
pondering before I was able to put the thing back in service shredding the
freakin ivy wall on the north side of the property. Pat

On Sun, 20 Apr 2008 05:41:16 -0700 (PDT), Manjo
wrote:

On Apr 19, 11:00*am, dpb wrote:
Manjo wrote:
I have a leaf blower that uses a 5 hp B&S "L" head engine. *...
...
The leaf blower was starting to run poorly last fall. *This spring it
started right up, but after4-5 seconds after running smoothly at
proper speed, it will slowly loose rpms and finally stop after 15-20
seconds.

I have cleaned the pick-up tube, replaced the carburetor diaphragm
fuel pump along with the gaskets between the carb and the fuel tank,
and the gasket between the carb and the engine. *I've also
disconnected the engine ground wire that normally kills the engine
when the throttle is tuned full off. *But after doing all this the
engine still will not stay running for more than 30 - 40 seconds.

Thanks in advance for any tips, suggestions, or coments.

I've not read the rest of the thread but noted you were apparently still
searching --

Anybody suggested checking the exhaust screen (I'm assuming it has one)
for C deposits? *Sounds like it could be clogged w/ buildup which will
cause such symptoms...

--- Hide quoted text -

- Show quoted text -

The exhaust has not been checked. I did put my hand near the exhaust
canister and I could feel puffs of air as the engine ran at normal
rpm. But now that you mention this, the air pressure felt a little
low or soft. I'll pull the can and check it today. Manjo

The crankcase has a breather also. See parts 8 & 9. This allows gases
to escape out the crankcase. They can be clogged, but cleaned easily.

On Sun, 20 Apr 2008 05:36:49 -0700 (PDT), Manjo
wrote:

How about checking around the head gasket for leaks. I had a lawnmower
engine that exhibited a similar problem.- Hide quoted text -

- Show quoted text -

I know it doesn't do much good, but I did do a visual check of the
head gasket edges. Nothing unusual, but I'll check it with some sudsy
water today. I lent out my leak down tester (I hope to get back soon)
so I had to use a standard cylinder compression tester. I got
consistent readings of 74 psi with a warm (not hot) engine. I think
this is a good reading since it's a small cylinder, unlike an auto
engine cylinder. Manjo

If you did have a leak at the head gasket; you might hear a slight
whistle sound with the engine running. A blown gasket and I doubt the
engine would run, as the power combustion goes out the passage/leak.

On Sun, 20 Apr 2008 05:54:36 -0700 (PDT), Manjo
wrote:

I did a similar spark plug test a few days ago. I left the spark plug
in the engine port and put another spark plug in the cap and held it
to the top of the first and I was able to start the engine.

If you pull the plug out and test, there is now no compression. Pull
the rope and cycle through several power strokes and you can get a
better exam of the spark.

Oren wrote:
On Sun, 20 Apr 2008 05:36:49 -0700 (PDT), Manjo
wrote:
....
so I had to use a standard cylinder compression tester. I got
consistent readings of 74 psi ...

If you did have a leak at the head gasket; you might hear a slight
whistle sound with the engine running. A blown gasket and I doubt the
engine would run, as the power combustion goes out the passage/leak.

A "blown" gasket wouldn't give 75 psi, either...

--

On Apr 20, 10:16 am, "patrick mitchel" wrote:
Here's a wild thought; I read that it's a leaf blower. Is there a belt
drive in it? Was thinking of a way to power the engine using a drive to spin
the motor - with the plug out and grounded. Long enough to see if the coil
overheats and breaks down and loses spark. That would at least remove one of
the variables. Having gone through a series of question with a 8 hp briggs L
head (finally found an intermittent intake valve) that caused me some
pondering before I was able to put the thing back in service shredding the
freakin ivy wall on the north side of the property. Pat

The engine needs to RUN in order to heat the coil to thermal fault.
Spinning has little to do with it.