This one has me hornswoggled. I have a fairly new push mower your typical low-end briggs and stratton engine. The thing starts perfectly, runs perfectly for about 20 minutes and then starts sputtering. Not enough to stop the engine but like it is choking or something.

Any ideas?

On 5/16/14, 7:08 PM, noname wrote:
This one has me hornswoggled. I have a fairly new push mower your typical low-end briggs and stratton engine. The thing starts perfectly, runs perfectly for about 20 minutes and then starts sputtering. Not enough to stop the engine but like it is choking or something.

Any ideas?


One thing to check for is a clogged vent hole in the gas cap.

On Fri, 16 May 2014 19:36:57 -0400, Retired wrote:

On 5/16/14, 7:08 PM, noname wrote:
This one has me hornswoggled. I have a fairly new push mower your typical low-end briggs and stratton engine. The thing starts perfectly, runs perfectly for about 20 minutes and then starts sputtering. Not enough to stop the engine but like it is choking or something.

Any ideas?


One thing to check for is a clogged vent hole in the gas cap.

+

Are you pushing the mower on a steep bank?

Try removing the air filter, leave it off and report back if it runs.

--
....no commas used for Bob Villa. Hornswoggle my confuse him.

On 5/16/2014 7:08 PM, noname wrote:
This one has me hornswoggled. I have a fairly
new push mower your typical low-end briggs and
stratton engine. The thing starts perfectly,
runs perfectly for about 20 minutes and then
starts sputtering. Not enough to stop the engine
but like it is choking or something.

Any ideas?

Some of the possible causes:

Bad ignition coil, fails when hot
Bad brand of motor oil
Valve clearance
Clogged vent on gas cap

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

On Saturday, May 17, 2014 6:56:26 AM UTC-4, Stormin Mormon wrote:
On 5/16/2014 7:08 PM, noname wrote:

This one has me hornswoggled. I have a fairly

new push mower your typical low-end briggs and

stratton engine. The thing starts perfectly,

runs perfectly for about 20 minutes and then

starts sputtering. Not enough to stop the engine

but like it is choking or something.



Any ideas?



Some of the possible causes:



Bad ignition coil, fails when hot

Bad brand of motor oil

That's a new one. How would that cause the symptom?

Is it still under warranty?

Dave M.

On 5/17/2014 8:03 AM, trader_4 wrote:
On Saturday, May 17, 2014 6:56:26 AM UTC-4, Stormin Mormon wrote:

Bad brand of motor oil

That's a new one. How would that cause the symptom?


Some years ago, I met a mechanic who assured me
that cheap motor oil doesn't work properly in
air cooled small engines. I am not sure the reason.
I did put cheap oil in a lawn mower I sold, and
it came back "doesn't run right". Drain it, and
put in good oil, and the next customer was happy.
Of course, that's not scientific. Beyond that, not
sure.

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

On Saturday, May 17, 2014 9:47:09 AM UTC-4, Stormin Mormon wrote:
On 5/17/2014 8:03 AM, trader_4 wrote:

On Saturday, May 17, 2014 6:56:26 AM UTC-4, Stormin Mormon wrote:



Bad brand of motor oil



That's a new one. How would that cause the symptom?





Some years ago, I met a mechanic who assured me

that cheap motor oil doesn't work properly in

air cooled small engines. I am not sure the reason.

I did put cheap oil in a lawn mower I sold, and

it came back "doesn't run right". Drain it, and

put in good oil, and the next customer was happy.

Of course, that's not scientific. Beyond that, not

sure.



--

.

Christopher A. Young

Learn about Jesus

www.lds.org

.

I've tried everything. New gas, plug, changed the oil, took the air filter off, checked the gap cap for venting. Also, took off the engine cover where the flywheel is to make sure it wasn't clogged either.

With the air filter off I do notice something though, when the thing is sputtering the little choke valve that is over the carb and is attached to the throttle and the little springs just keeps popping open and closed over and over again. Make sense why it is sputtering then but I can't see anything wrong with it. I tried fiddling with the springs and experimenting with restricting it, but doesn't seem to help. My guess is either something is making the thing choke on and off over and over or it is hooked up wrong.

Further debugging ideas anyone? Thanks.

On Sunday, May 18, 2014 8:09:36 PM UTC-4, noname wrote:
On Saturday, May 17, 2014 9:47:09 AM UTC-4, Stormin Mormon wrote:

On 5/17/2014 8:03 AM, trader_4 wrote:



On Saturday, May 17, 2014 6:56:26 AM UTC-4, Stormin Mormon wrote:







Bad brand of motor oil







That's a new one. How would that cause the symptom?











Some years ago, I met a mechanic who assured me



that cheap motor oil doesn't work properly in



air cooled small engines. I am not sure the reason.



I did put cheap oil in a lawn mower I sold, and



it came back "doesn't run right". Drain it, and



put in good oil, and the next customer was happy.



Of course, that's not scientific. Beyond that, not



sure.







--



.



Christopher A. Young



Learn about Jesus



www.lds.org



.



I've tried everything. New gas, plug, changed the oil, took the air filter off, checked the gap cap for venting. Also, took off the engine cover where the flywheel is to make sure it wasn't clogged either.



With the air filter off I do notice something though, when the thing is sputtering the little choke valve that is over the carb and is attached to the throttle and the little springs just keeps popping open and closed over and over again. Make sense why it is sputtering then but I can't see anything wrong with it. I tried fiddling with the springs and experimenting with restricting it, but doesn't seem to help. My guess is either something is making the thing choke on and off over and over or it is hooked up wrong..



Further debugging ideas anyone? Thanks.

Oh..jeez I think the long governor spring is attached to the wrong place. There isn't enough tension against the governor arm and that is why it is flapping. Too dark to go and try this fix out... does this make sense?

On Sun, 18 May 2014 17:09:36 -0700 (PDT), noname
wrote:

With the air filter off
I do notice something though, when the thing is sputtering the little
choke valve that is over the carb and is attached to the throttle and
the little springs just keeps popping open and closed over and over
again. Make sense why it is sputtering then but I can't see anything
wrong with it. I tried fiddling with the springs and experimenting with
restricting it, but doesn't seem to help. My guess is either something
is making the thing choke on and off over and over or it is hooked up
wrong.

Further debugging ideas anyone? Thanks.

Hold the choke open or put a wire on it to make sure it stays open.
If that dont fix it, check to make sure the gas filter or screen inside
gas tank is not plugging up. Another thing, is the carb loose? Tighten
carb screws or bolts incl. intake tube. (manifold).

Sometimes a magneto will begin to fail when its hot, due to expansion
causing some high voltage leaking. Electronic ignition modules (if yiou
have one) can get screwy when hot too, or the capacitor at the points
can be dying.

On 5/18/2014 8:22 PM, noname wrote:
Further debugging ideas anyone? Thanks.

Oh..jeez I think the long governor spring is attached to the wrong place. There isn't enough tension against the governor arm and that is why it is flapping. Too dark to go and try this fix out... does this make sense?

Could be. The governor springs sometimes get rusty
and don't spring correctly.

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

On Fri, 16 May 2014 16:08:01 -0700 (PDT), noname
wrote:

This one has me hornswoggled. I have a fairly new push mower your typical low-end briggs and stratton engine. The thing starts perfectly, runs perfectly for about 20 minutes and then starts sputtering. Not enough to stop the engine but like it is choking or something.

Any ideas?


I've had mowers do that when they have water in the gas. Makes no
sense to me that they run right for a while and then run poorly but
draining the carb bowl clears it up. I've also had this happen when
there appears to have been something not even visible clogging the jet
in the carb but taking the jet out, blowing it out and buttoning it
back up made it run perfect afterward.

On 5/18/2014 8:09 PM, noname wrote:
I've tried everything. New gas, plug, changed the
oil, took the air filter off, checked the gap cap for
venting. Also, took off the engine cover where the
flywheel is to make sure it wasn't clogged either.

With the air filter off I do notice something though,
when the thing is sputtering the little choke valve
that is over the carb and is attached to the throttle
and the little springs just keeps popping open and
closed over and over again. Make sense why it is
sputtering then but I can't see anything wrong with
it. I tried fiddling with the springs and experimenting
with restricting it, but doesn't seem to help. My guess
is either something is making the thing choke on and off
over and over or it is hooked up wrong.

Further debugging ideas anyone? Thanks.


It occurs to me that the choke opening might be a
symptom of faltering, not the cause of the faltering.
ATM, my guess is bad ignition coil.

If it were valve clearance problem, it would fade
and die until it's cooled down.

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

On 05/18/2014 05:22 PM, noname wrote:

Oh..jeez I think the long governor spring is attached to the wrong
place. There isn't enough tension against the governor arm and that
is why it is flapping. Too dark to go and try this fix out... does
this make sense?

Yes, governor springs are incredibly touchy, but it wouldn't explain why
it is running for 20 minutes before it starts causing trouble.

One possibility is that you have a bad coil, the symptoms of which do
not show up until it warms up.

Jon

On Sun, 18 May 2014 17:09:36 -0700 (PDT), noname
wrote:

I've tried everything. New gas, plug, changed the oil, took the air filter off, checked the gap cap for venting. Also, took off the engine cover where the flywheel is to make sure it wasn't clogged either.

With the air filter off I do notice something though, when the thing is sputtering the little choke valve that is over the carb and is attached to the throttle and the little springs just keeps popping open and closed over and over again. Make sense why it is sputtering then but I can't see anything wrong with it. I tried fiddling with the springs and experimenting with restricting it, but doesn't seem to help. My guess is either something is making the thing choke on and off over and over or it is hooked up wrong.

Further debugging ideas anyone? Thanks.

Thoughts:

If the butter fly choke baffle fluctuates; is there air & fuel screw
on the carb? Adjusting the air and fuel jet screws may work. They
both mix in the throat of the carb. Manually open the throttle. Adjust
a screw until the engine sounds better. Keep the RPM up, not at idle
"Tuned by Ear", as I learned.

--
"Dodgeball in Burkas" -- Greg Gutfeld

On Sun, 18 May 2014 22:45:56 -0400, Stormin Mormon
wrote:

On 5/18/2014 8:22 PM, noname wrote:
Further debugging ideas anyone? Thanks.

Oh..jeez I think the long governor spring is attached to the wrong place. There isn't enough tension against the governor arm and that is why it is flapping. Too dark to go and try this fix out... does this make sense?

Could be. The governor springs sometimes get rusty
and don't spring correctly.

Or a screw vibrated loose? Adjustment...

--
"Dodgeball in Burkas" -- Greg Gutfeld

On Mon, 19 May 2014 06:49:27 -0400, Stormin Mormon
wrote:

It occurs to me that the choke opening might be a
symptom of faltering, not the cause of the faltering.

Fuel & Air mixture at the choke baffle.

A worn baffle choke butterfly can stick and bind.