Just wondering what kind of hours you have on the machine ?

I doubt you have a bent connecting rod or blown gasket. You would have much lower compression if the gasket was bad.....

More likely a build up of carbon on the piston. worn out valve guides, worn out rings. Depending on the hours, if the cylinders are out of round. The varying rpm could be a governor issue.....For the fouling plugs, you could try a hotter spark plug, going up in the heat range to burn off the carbon......

The problem is that it is a JD.....Kawasaki builds the engine to JD specs. The only thing I know for sure is that the PTO end of the crank is different then the regular FH 601. So you have to go through a JD dealer. And pay JD prices.

Good luck.
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Just wondering what kind of hours you have on the machine ?

I doubt you have a bent connecting rod or blown gasket. You would have much lower compression if the gasket was bad.....

More likely a build up of carbon on the piston. worn out valve guides, worn out rings. Depending on the hours, if the cylinders are out of round. The varying rpm could be a governor issue.....For the fouling plugs, you could try a hotter spark plug, going up in the heat range to burn off the carbon......

The problem is that it is a JD.....Kawasaki builds the engine to JD specs. The only thing I know for sure is that the PTO end of the crank is different then the regular FH 601. So you have to go through a JD dealer. And pay JD prices.

Good luck.
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The engine only has 795 hrs. This problem has been slowly getting worse the last year. It has had a good puff of smoke when starting, but pretty much cleared up when running. The engine hesitates simultaneously with a small puff through the carb which tells me something wrong with the timing? While testing the engine the oil fill tube popped off and sprayed the whole engine with oil. I would not expect that pressure in the bottom of the engine? This would indicate worn piston rings and blowby, but the compression looks good? Try anything else before I tear down the engine?

 

Pulled flywheel. Key OK. Could timing gear have slipped some teeth on a backfire?

 

No, I don't think so unless you see damage teeth/missing teeth......
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Is there a good test for the new spark coils? Is it possible one of them misfires occasionally?

 

Is it possible one of them misfires occasionally?

The only thing that I know of that would cause a miss fire, is if the wire going to the coil was chaffed to cause a intermittent ground. There could be other things that I have never come across. But this kind of problem had me talking to myself out load

Coils either work, or they don't.
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