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post #1 of 3 Old 05-27-2010, 01:15 AM Thread Starter
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Kohler Command CV15S Ignition problem.

This engine has been causing me quite a lot of problems since I got it. I'll give you the history.

I got it and tried to fire it up. It ran, but only on full choke.

Took the carb apart, cleaned it and put it back on then it started starving the engine of gas.

Took the carb apart, cleaned the brass needle seat with polishing compound, put a new needle in, same problem

Traced the problem to the fuel shutoff solenoid on the carb bowl, disabled it put the carb back on and it flooded the cylinder with gas.

changed the oil, tried to start it, started right up, ran rough at all different speeds, no longer swamps the engine.

Now, just resumed work on it after a month of putting it aside, go to start it, nothing. It's got spark and I put some gas in the cylinder. Used the air gun to clear the gas out after it failed to start by sticking it in the spark plug hole.

Now, whenever I go to crank it, it just shoots flames out of the carburetor while cranking and finally it backfires. I'm thinking that it sheared a flywheel key and that got it out of time, but is it possible for the valves in an OHV engine to be part of the problem?

Any help would be appreciated.


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post #2 of 3 Old 05-27-2010, 04:35 AM
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Re: Kohler Command CV15S Ignition problem.

Walt Conner (probably the pre-eminent engine man here), is adamant about proper valve lash (especially on engines with compression release mechanisms). If the compression is poor, you might try running some Marvel Mystery oil in your fuel (or SLOWLY dribble some in the carb as the motor is pulled through) to lube the valve stems & guides. If the compression is good, the key or the valve lash is more likely
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post #3 of 3 Old 05-27-2010, 11:34 AM
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Re: Kohler Command CV15S Ignition problem.

If the intake valve were stuck open, it would suck in fuel/air mix, try to compress it, forcing it back out the carb, then light it off when the plug fired.
I think if you removed the air cleaner, you would also hear a wheezing sound as the mix came back through the carb or tried to get past a closed throttle butterfly.
The Kohler uses 'ACR' - automatic compression release - to ease cranking when trying to start the engine. It uses a spring loaded pin to hold the exhaust valve open longer below 700 rpm. That would exclude ACR from causing backfire throught the carburetor, I'd say.

Does this sound like what you are experiencing? Is there any reason to suspect a sheared woodruff key?

Last edited by tomw0; 05-27-2010 at 11:39 AM. Reason: add ACR
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