Easy Way to Clean Carb Jets on Kohler Command Twin Cyliner Engine

I've searched and read several threads here of similar issue as mine, and it sounds like my problem might be an ignition coil. I have a Simplicity Legacy mower with a Kohler 25. I was mowing on a slope when it started running very weak. I looked at the fuel gauge, and though I had about 1/2 tank, the slope was to the right, so the gauge was on E. I figured the fuel pickup was not getting ample fuel supply.

So I disengaged the mower, and eased it onto level ground, and worked the choke a little, which had no effect on it. Made it back to the garage, barely. I cleaned off the foam pre-screen, checked the plugs, checked the harness connector on the right side, all looked ok.

I narrowed it down to running on one cylinder, as I could pull the right spark plug wire off, and it had no effect. When I pulled the left, it would stop running. I swapped plugs to make sure it wasnt a bad plug, but the problem did not follow the sparkplug.

I connected an old Sears timing strobe light to each plug wire as it was running, and both sides made the timing light come on the same brightness.

I dont think it is fuel related. I filled up the tank, and ran it (on one cyl) for a few moments, no change. If the carb had clogged passages, choking it would have a more positive effect on how it runs, and both cylinders would be running, even somewhat intermittently. Now, only the left cyl is running.

Suggestions?

Just came in from checking the compression, left is about 160 and right is about 170. So the problem is most likely electrical?

Oh yeah, and my son had been mowing for about 2-3 hrs prior to when I got on, so everything was heat soaked pretty good when it started acting up.

Bad spark plug wire? If I understand your posts, the cylinder with the higher compression is not firing.

Bad spark plug wire? If I understand your posts, the cylinder with the higher compression is not firing.

Yes, right cyl - 170# compression, is not firing. Plug is sparking though. I guess could be plug wire, Smart Spark module, or ignition module? Maybe air gap wrong? Mice are always making a nest around the drive shaft, maybe they chewed on some of the wires ????? I really dont want to pull that engine. :confused2:

I'm a little confused. One cylinder isn't firing, but that cylinder has spark?

I just got through replacing a $35 ignition module on a single cylinder Kohler magnum--all I had to do was pull the sheet metal shrouds off and replaced it with no problem. That cured mine going dead after it got hot. I didn't have to pull the engine--just took my time and it went fine.

I would remove both rocker arm covers and both spark plugs. Then rotate the engine by hand while observing the behavior, lift and condition of the rocker arms and push rods. Kohler had problems with the rocker arms on the earlier Command engs and have upgrade/ replacements available.

I'm a little confused. One cylinder isn't firing, but that cylinder has spark?

I just got through replacing a $35 ignition module on a single cylinder Kohler magnum--all I had to do was pull the sheet metal shrouds off and replaced it with no problem. That cured mine going dead after it got hot. I didn't have to pull the engine--just took my time and it went fine.

Yes, the right cyl is not firing, but has spark. I've verified with the sparkplug grounded against the head while cranking it, and with a strobe timing light. I've swapped plugs and the problem stayed with the cyl, so it's not plugs. Since it has spark, it could be a timing issue.

I would remove both rocker arm covers and both spark plugs. Then rotate the engine by hand while observing the behavior, lift and condition of the rocker arms and push rods. Kohler had problems with the rocker arms on the earlier Command engs and have upgrade/ replacements available.

If there is a problem with the rocker arms/valves, wouldnt it show up in the compression? The right cyl (no run) is about 170 and the left (that runs) is about 160.

Thanks for the suggestions. Still scratching my head. I plan on stopping by the shop today and see if they can test the components if I bring them in.

Not necessarily, I've seen some strange indications resulting from bent push rods and broken rockers. I suggested this because it is a quick and simple test and frequently renders conclusive results.

Not necessarily, I've seen some strange indications resulting from bent push rods and broken rockers. I suggested this because it is a quick and simple test and frequently renders conclusive results.

Good point. I just pulled the rocker cover off, and cranked it over (plugs out), and everything looked good.

Now I have a bolt to replace and a hole to retap. Seems the factory cross-threaded it. I knew it would snap off, but didnt. Seems like always something .....

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Source: https://www.tractorbynet.com/forums/threads/kohler-running-on-one-cylinder.170531/

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