I'm trying to help my daughter with her lawn mower (Sears, Craftsman). In
the past I've always been able to start them by spraying gas onto the air
filter. This time no luck. I have spark. The ignition is electronic. The
manual says that one of the possibilities is a loose blade. I have the
blade off the machine.
How would the engine know, or care, that the blade is loose or off?
Any ideas?

Thanks, Ivan Vegvary

Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

"Richard J Kinch" wrote in message
.. .
Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

Richard (and your manual) are correct. The crankshaft will not have enough
momentum to get through the cycles and actually start running without the
blade firmly attached. And you'll feel the difference when you 'pull it
through'.

The other problem is you "spraying gas onto the air filter". Not only is
this a fire hazard, but it will also score the cylinder wall (sooner or
later). Definitely not good for your equipment.

Uh, because the blade is the flywheel on a mower engine yidiot .
JR
Dweller in the cellar

Ivan Vegvary wrote:

I'm trying to help my daughter with her lawn mower (Sears, Craftsman). In
the past I've always been able to start them by spraying gas onto the air
filter. This time no luck. I have spark. The ignition is electronic. The
manual says that one of the possibilities is a loose blade. I have the
blade off the machine.
How would the engine know, or care, that the blade is loose or off?
Any ideas?

Thanks, Ivan Vegvary




--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth
If you're not the lead dog, the view never changes
Doubt yourself, and the real world will eat you alive
The world doesn't revolve around you, it revolves around me
No skeletons in the closet; just decomposing corpses
--------------------------------------------------------------
Dependence is Vulnerability:
--------------------------------------------------------------
"Open the Pod Bay Doors please, Hal"
"I'm sorry, Dave, I'm afraid I can't do that.."

reader writes:

The other problem is you "spraying gas onto the air filter". Not only is
this a fire hazard, but it will also score the cylinder wall (sooner or
later). Definitely not good for your equipment.

Why is fuel vapor from the filter any different than from the normal
carbueration?

On Tue, 09 May 2006 05:46:01 GMT, "reader" wrote:


"Richard J Kinch" wrote in message
. ..
Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

Richard (and your manual) are correct. The crankshaft will not have enough
momentum to get through the cycles and actually start running without the
blade firmly attached. And you'll feel the difference when you 'pull it
through'.

The other problem is you "spraying gas onto the air filter". Not only is
this a fire hazard, but it will also score the cylinder wall (sooner or
later). Definitely not good for your equipment.

I used the propane trickling into the carb trick the other day,
getting my lawn mower fired up for the summer season. Worked just
hunky dory

Gunner

Now why doesn't this surprise me one bit?

That's easy.... you're too dull witted to be capable of surprise. What
little synaptic ability you do possess is stretched to the limit with
life support. If you diverted power to the critical thought processors
you'd asphyxiate in a matter of minutes.

George Orwell

In article ,
Gunner wrote:

I used the propane trickling into the carb trick the other day,
getting my lawn mower fired up for the summer season. Worked just
hunky dory

If it doesn't fire with propane the spark might be weak and not fire
under pressure. Try 1/2 the gap, on the plug as an experiment.

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/

Nonsense. If that were the case things like roto-tillers, go-karts, edgers,
and other things that start with 0 load wouldn't start.

"Richard J Kinch" wrote in message
.. .
Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

They are fitted with heavier flywheels for that reason. A rotary mower
doesn't need that heavy a flywheel as the blade acts as one.

Gary H wrote:

Nonsense. If that were the case things like roto-tillers, go-karts, edgers,
and other things that start with 0 load wouldn't start.

"Richard J Kinch" wrote in message
. ..

Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

Once you have the blade back on if the carb has a foam air filter that
requires oiling you might make sure its oiled. When they dry out they
can allow the engine to run lean and be more difficult to start.

Ivan Vegvary wrote:

I'm trying to help my daughter with her lawn mower (Sears, Craftsman). In
the past I've always been able to start them by spraying gas onto the air
filter. This time no luck. I have spark. The ignition is electronic. The
manual says that one of the possibilities is a loose blade. I have the
blade off the machine.
How would the engine know, or care, that the blade is loose or off?
Any ideas?

Thanks, Ivan Vegvary

"David Billington" wrote in message
...
Once you have the blade back on if the carb has a foam air filter that
requires oiling you might make sure its oiled. When they dry out they can
allow the engine to run lean and be more difficult to start.

Ivan Vegvary wrote:

I'm trying to help my daughter with her lawn mower (Sears, Craftsman). In
the past I've always been able to start them by spraying gas onto the air
filter. This time no luck. I have spark. The ignition is electronic.
The manual says that one of the possibilities is a loose blade. I have
the blade off the machine.
How would the engine know, or care, that the blade is loose or off?
Any ideas?

Thanks, Ivan Vegvary



I'll bet you've got an exhaust valve stuck open. Has it been sitting all
winter and this is the first start? If the valve's stuck open, take the
head off and hit the stem with a little oil, tap it back down and turn the
engine through until it starts opening a closing normally. Hope this helps.

Make sure that the gas is brand new. Even if she ran the mower until
it was dry at the end of last season, there can still be old gas in the
carburetor bowl. If draining the tank and then putting in new gas
doesn't work, take the carburetor bowl off, drain it, clean it, put it
back on, and then try it again. You won't need to take the carburetor
off. Remove the plug to see if you have carbon between the electrodes.
This carbon can build up to the point where the gap disappears
completely. If you have a gap, though, you should be okay. Clean the
air filter. As a last resort, you can use starting fluid
_conservatively_, and understand that this might do more harm than
good, if you have not done everything else possible first. If all else
fails, move to Austin, and go into the music business. Just kidding.

Mike Mandaville

Check the key under the flywheel. They a usually made of aluminum and
designed to shear. Even if the key is only slightly deformed, it can throw
of the timing.

On Tue, 09 May 2006 11:32:38 GMT, "Gary H"
wrote:

Nonsense. If that were the case things like roto-tillers, go-karts, edgers,
and other things that start with 0 load wouldn't start.

"Richard J Kinch" wrote in message
. ..
Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

Gary-take a look at the flywheels in vertical shaft rotary mowers and
in horizontal shaft motors. You will see an aluminum flywheel in the
rotary mower motor and a cast iron one in the horizontal one. And
another eye opener is to try to start that rotary mower without the
blade. Oftentimes what happens is that the motor, lacking enough
flywheel mass, will start to rotate backwards when it fires. When this
happens the handle will be torn from your hand instantly. DAMHITK.
ERS

Eric R Snow wrote:
On Tue, 09 May 2006 11:32:38 GMT, "Gary H"
wrote:

Nonsense. If that were the case things like roto-tillers, go-karts,
edgers, and other things that start with 0 load wouldn't start.

"Richard J Kinch" wrote in message
.. .
Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

Gary-take a look at the flywheels in vertical shaft rotary mowers and
in horizontal shaft motors. You will see an aluminum flywheel in the
rotary mower motor and a cast iron one in the horizontal one. And
another eye opener is to try to start that rotary mower without the
blade. Oftentimes what happens is that the motor, lacking enough
flywheel mass, will start to rotate backwards when it fires. When this
happens the handle will be torn from your hand instantly. DAMHITK.
ERS
AND if you have a real good grip on said handle you will be in pain for a
considerable time!

Ken.
--
Volunteer your idle computer time for cancer research
http//www.grid.org/download/gold/download.htm
Return address courtesy of Spammotel http://www.spammotel.com/

Thanks everybody!!!!!

Put the blade back on and the mower started on the first pull.
As recited by other posters, YES, without the blade the rope DOES get ripped
out of your hand and worse.

Thanks again. This is the best group for saving my bacon.

Ivan Vegvary

As recited by other posters, YES, without the blade the rope DOES get
ripped
out of your hand and worse.

DAMN, no video?

Maybe there is some truth to what you say but when I was a kid my dad and I
would make go karts with normal lawn mower engines (used a fan belt with a
90 deg twist) and they started just fine with no flywheel at all.

"Eric R Snow" wrote in message
...
On Tue, 09 May 2006 11:32:38 GMT, "Gary H"
wrote:

Nonsense. If that were the case things like roto-tillers, go-karts,
edgers,
and other things that start with 0 load wouldn't start.

"Richard J Kinch" wrote in message
...
Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

Gary-take a look at the flywheels in vertical shaft rotary mowers and
in horizontal shaft motors. You will see an aluminum flywheel in the
rotary mower motor and a cast iron one in the horizontal one. And
another eye opener is to try to start that rotary mower without the
blade. Oftentimes what happens is that the motor, lacking enough
flywheel mass, will start to rotate backwards when it fires. When this
happens the handle will be torn from your hand instantly. DAMHITK.
ERS

I meant no flywheel other than the one on top. But I am not saying I don't
believe you. If I recall correctly I did have to pull the heck out of the
rope to get it going.

"Gary H" wrote in message
t...
Maybe there is some truth to what you say but when I was a kid my dad and
I would make go karts with normal lawn mower engines (used a fan belt with
a 90 deg twist) and they started just fine with no flywheel at all.

"Eric R Snow" wrote in message
...
On Tue, 09 May 2006 11:32:38 GMT, "Gary H"
wrote:

Nonsense. If that were the case things like roto-tillers, go-karts,
edgers,
and other things that start with 0 load wouldn't start.

"Richard J Kinch" wrote in message
1...
Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.

Gary-take a look at the flywheels in vertical shaft rotary mowers and
in horizontal shaft motors. You will see an aluminum flywheel in the
rotary mower motor and a cast iron one in the horizontal one. And
another eye opener is to try to start that rotary mower without the
blade. Oftentimes what happens is that the motor, lacking enough
flywheel mass, will start to rotate backwards when it fires. When this
happens the handle will be torn from your hand instantly. DAMHITK.
ERS

"Gary H" wrote in message
t...
Maybe there is some truth to what you say but when I was a kid my dad and
I would make go karts with normal lawn mower engines (used a fan belt with
a 90 deg twist) and they started just fine with no flywheel at all.


There is allot of truth to it. Maybe not all, but most lawnmower engines
need the blade attached to act as a flywheel. It is damned hard to even pull
some of them over without a blade as the engine will kick back.
Greg

Maybe there is some truth to what you say but when I was a kid my dad and
I would make go karts with normal lawn mower engines (used a fan belt
with a 90 deg twist) and they started just fine with no flywheel at all.


There is allot of truth to it. Maybe not all, but most lawnmower engines
need the blade attached to act as a flywheel. It is damned hard to even
pull some of them over without a blade as the engine will kick back.
Greg


Interesting. My experience comes from tinkering with lawnmower engines over
25 yrs ago. I don't remember ever seeing anything other than a cast iron
flywheel on any of them. Perhaps that is why I could start them OK back
then. Beats me.

On Tue, 09 May 2006 20:20:27 GMT, "Tom Gardner"
wrote:

As recited by other posters, YES, without the blade the rope DOES get
ripped out of your hand and worse.

DAMN, no video?

Damn, no snarky remarks by Tom Bergeron, either.

-- Bruce --

Gary H wrote:

Maybe there is some truth to what you say but when I was a kid my dad and
I would make go karts with normal lawn mower engines (used a fan belt
with a 90 deg twist) and they started just fine with no flywheel at all.

There is allot of truth to it. Maybe not all, but most lawnmower engines
need the blade attached to act as a flywheel. It is damned hard to even
pull some of them over without a blade as the engine will kick back.
Greg


Interesting. My experience comes from tinkering with lawnmower engines over
25 yrs ago. I don't remember ever seeing anything other than a cast iron
flywheel on any of them. Perhaps that is why I could start them OK back
then. Beats me.


I've got to say my experience with vertical shaft lawn mower engines was
about that long ago and mainly with B&S engines and the odd POS Sears
Tecumseh and I can't remember seeing a CI flywheel on any of them, all
alloy with the magnets cast in. I had tried to start a couple without
the blade and generally no joy.

On Tue, 09 May 2006 11:32:38 GMT, "Gary H"
wrote:

Nonsense. If that were the case things like roto-tillers, go-karts, edgers,
and other things that start with 0 load wouldn't start.

"Richard J Kinch" wrote in message
. ..
Ivan Vegvary writes:

How would the engine know, or care, that the blade is loose or off?

It acts as a flywheel.



This is CORRECT. Lawn mower engines have light aluminum flywheels and
will NOT start without the blade attached. Garden tiller and belt
driven mower engines (and go-cart engines) have heavier cast iron
flywheels which will allow the engine to start and run with no load.

It is a design quirk, which like it or not, is FACT.

*** Posted via a free Usenet account from http://www.teranews.com ***

You have grass at you place? I'm surprised. It's so dry and dusty
there...

reader writes:

The other problem is you "spraying gas onto the air filter". Not only is
this a fire hazard, but it will also score the cylinder wall (sooner or
later). Definitely not good for your equipment.

Why is fuel vapor from the filter any different than from the normal
carbueration?
Actually, it's flushing the grit through the filter into the air
intake where it gets eaten by the engine...and fuel isn't
vaporized in those little carbs very well, but if you have an air
filter full of vapor and saturated with fuel, one little backfire and
the excitement begins....
Ken.

I just started my cratfsman mower with tecumseh engine without the
blade. Runs fine that way. Mower was free to me. owner said it wouldn't
run. SEars said 150 bux to fix it. It came with no blade or hub.
Got those, now can't tighten bolt enough to not come loose within 5
seconds.
Is Locktite the answer?

daniel peterman wrote:
I just started my cratfsman mower with tecumseh engine without the
blade. Runs fine that way. Mower was free to me. owner said it wouldn't
run. SEars said 150 bux to fix it. It came with no blade or hub.
Got those, now can't tighten bolt enough to not come loose within 5
seconds.
Is Locktite the answer?

That and a fresh lockwasher would be the
next thing I'd try.

On Thu, 11 May 2006 10:05:05 -0700, Jim Stewart
wrote:

daniel peterman wrote:
I just started my cratfsman mower with tecumseh engine without the
blade. Runs fine that way. Mower was free to me. owner said it wouldn't
run. SEars said 150 bux to fix it. It came with no blade or hub.
Got those, now can't tighten bolt enough to not come loose within 5
seconds.
Is Locktite the answer?

That and a fresh lockwasher would be the
next thing I'd try.
You will probably live to regret using locktite. The blade on my mower
is keyed to the hub with #10 x 1/4 soft iron rivets as shear pins, the
hub in turn is keyed to the shaft with a woodruff key, I ensure that
the threads are clean, apply anti seize, tighten the bolt finger
tight, then hold the blade and snug up the bolt. MAKE SURE THE
IGNITION IS DISSABLED WHEN DOING THIS or you will be like the beer
drinker who decided it would be easy to use his rotary mower to rim
the hedge. They call him "Stumpy" now cause he has eight of them!
Gerry :-)}
London, Canada

thanks guys. I'll give the lockwasher a chance then locktite as last
resort.