2N troubles

Res133cue · Jul 17, 2014

Seems as I get one thing straightened out another problem pops up. So here is my situation now. Starts fine and runs good for about 20 minutes running my finish mower. After that it seems to loose HP and starts to sputter. It will still run and mow decent in reverse at this point. Once. Shut off the PTO it will run and drive ok for a while before the sputtering starts with no load. Have good fuel and spark is good cold and coil is new. I observed the flywheel today and it spins fine cold, I did notice once it starts to sputter under load the flywheel turns out of balance. Once the PTO is off it turns true again. Also when the sputtering it appears that exhaust is coming back through the intake pipe.
So my question is have I lost a bearing that is causing the crank to wobble and an exhaust valve to remain open? Is it just a valve sticking? Any other ideas I may have missed?

Bruce (VA) · Jul 17, 2014

" have I lost a bearing that is causing the crank to wobble and an exhaust valve to remain open? Is it just a valve sticking?"

If you lost a bearing that caused the crank to wobble, that engine would continue to run for about 2 seconds.

And valves don't stick open after the engine heats up.

" Have good fuel and spark is good cold and coil is new."

That's probably not the case.

Did you check for fuel and spark as soon as it started to stumble? Not five minutes later, but immediately?

Tell us exactly how you checked for fuel & spark.

It's easy to over-think these problems......90% of them turn out to be simple fuel or spark issues.
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Res133cue · Jul 17, 2014

Checked fuel by removing the drain plug on the bottom of the carb. Checked for spark with my inline spark checker. When it starts to stumble air is going in the intake and what smells like exhaust is blowing out of it.

Bruce(VA) · Jul 17, 2014

Did you check spark and fuel as soon as it began to stumble?

HCooke · Jul 17, 2014

I'm with Bruce, it's either a fuel problem or a spark problem. What does the spark look like when it starts to run rough? Also, is this 6 volt or a 12 volt conversion? What is the intake pipe? And how can you see the flywheel?

Res133cue · Jul 20, 2014

So on start up it has a strong regular spark to all the plugs.
Once it starts to stumble the spark is still strong but not regular
any more. I was only able to check 3&4 but I figure 1&2 must
be doing it as well. So condenser, points or coil? The coil is
brand new out of the box back in May. The distributor cover
and rotor button are brand new last month. I have a video but I
am not sure how to attach it to this post.

Bruce (VA) · Jul 20, 2014

As Harold asked........

Is the tractor 6v or 12v?

" So condenser, points or coil?"

In order of probability:

1. Ignition switch

2. Points

3. Condenser

4. Loose/corroded bad wiring

5. coil

Jump the ignition switch & see what happens. If that doesn't work, time for new points & a condenser.

" The coil is brand new out of the box back in May. The distributor cover and rotor button are brand new last month. "

So.......you replaced the parts least likely to fail (coil, cap & rotor) and ignored the points? Or did they look ok? Did you check the gap?
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2N troubles

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Bruce (VA)

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