I have a Kohler cv15s and it was running poorly. It would start and idle but it sounded like it was missing.
Here is a list of everything I did to this motor from the abyss
After each procedure I checked to see if it ran good.
1. Cleaned carb
2. used known "good carb"
3. Leak down, air leaking from breather, but not any valves
4. replaced head gasket, it was leaking although it had 125lbs compression
5. checked flywheel key
6. replaced igition module with known good one.
7. replaced lifters with known good ones
8. checked all grounds and wiring,
9. used good plug
10. Cursed the engine, kicked it, stubbed my toe.

Is there something I am missing here?????????????????
Any suggestions?
Thanks in advance

I would check the fuel lines for blockage and vent on fuel cap. if it has a primer check hose for cracks (air leak). you have covered most of what I would have checked or done.
is the gas new. if the gas was bought in the winter, is has added stuff for the cold weather but it collects water. cars are not bothered by the small amount but little engines are.

hope this helps and good luck

I have a Kohler cv15s and it was running poorly. It would start and idle but it sounded like it was missing.
Here is a list of everything I did to this motor from the abyss
After each procedure I checked to see if it ran good.
1. Cleaned carb
2. used known "good carb"
3. Leak down, air leaking from breather, but not any valves
4. replaced head gasket, it was leaking although it had 125lbs compression
5. checked flywheel key
6. replaced igition module with known good one.
7. replaced lifters with known good ones
8. checked all grounds and wiring,
9. used good plug
10. Cursed the engine, kicked it, stubbed my toe.

Is there something I am missing here?????????????????
Any suggestions?
Thanks in advance

I had a "Kohler from heck" experience on a CV15 last year that was similar,and I did all the things you have done,and the solution was replacing the cam.The lobes were worn down to like nothing.On this unit,it would run at no load speeds ok,but if you engaed the pto it would run rich.Taking off the airfilter made it a little better.Ran great without a muffler.Swapped mufflers with a known good one,no difference.So if any of this sounds like what you are experiencing,maybe consider that?

Steve