I bought Max IV with a Kohler M20 twin cylinder engine. It ides fine starts pretty easy but lacks power and wants to almost stall on hills. I have cleaned the carb and checked for spark which it has. It seems to have plenty of compression blows my thumb off the spark plug hole with plug out while cranking. What I have noticed is while running when removing plug wire from left side it will spit and sputter and continue to run. If I replace the plug wire it smooths out again. If I remove the plug wire from the opposite side it will stall out. I have tried switching spark plugs to opposite sides and the same side will continue to stall out. Runs smooth at idle but under load lacks power. Could it be a weak coil and is it possible to swap plug wires to the opposite cylinder or would it damage something? Any other suggestions?

Maybe a bad plug wire. Can you test it with a circuit tester?

Does it get worse the longer it runs?

Do a compression check (not the thumb over the hole) LOL

Not sure if it gets worse I haven't ridden it more than about 10-15 minutes at a time.I have a compression tester but read many have automatic compression release valves so not an accurate test.

adjust the valves.

Clean the valve trains , seen this on some of the OHV models , they get hung up sometimes with carbon or gunk. Pull the small cover over the valves and check to see if they are closing properly.

I will check them tomorrow hope it helps thanks.

You cannot just swap plug wires, since the spark is timed. When you pull off the wire and it stalls, it is more than likely the coil on the opposite side since it will want to run somewhat on the good side. It has been many yrs since I worked on a Kohler but it may have a cdi unit under the flywheel shroud.

I did verify spark with an inline spark tester to each cylinder while it was running. Both sides appeared to have the same spark. Neither side more than the other looking at the inline tester. I used a compression tester and both cylinders are right at 90 psi. I tried manually moving the governor linkage to raise the rpms and then pulling the plug wire and the same thing happens runs a little rougher on the one side and once the other side is pulled it will stall and not run on the other side. I did not get a chance to tear it all the way down to look at the valves more disassembly required than I had time for this evening. Could it still be valves not sealing up with equal compression or maybe still CDI? Any other suggestions?

easy way to check how well the valves are seating is to hook some compressed air through the spark plug hole and watch for blow by out the carb or muffler.

I am trying to think if the kholer engines have the diodes in the wiring for the coils. I know B&S engines do. And...they sorta act like what your kholer is doing when they start going bad. You might check in the wiring just to see if it does have the diodes. They are easily checked with a good VOM if they are there.

I was just having trouble starting a Kohler. It was a dirty air filter.

Check your coil(s). See if they ohm out within specs.

Russ

I got the head off now on the side that runs when the plug wire is pulled. The valves appear to be sealing up good. Just checked valve clearance intake and exhaust are both within spec. How do I test the coil I have a voltmeter and easy access to the coil at this point just don't understand how to do it?

http://resources.kohler.com/power/kohler/enginesUS/pdf/tp_2204_b.pdf

Section 8, page 8.2,8.3

Thank you Half ton