I don't see this engine on parts look up. What is it on? What gasket exactly are they continually replacing to correct the condition? Mechanical fuel pump or electric?

Thanks for answering. It is on a Simplicity tractor. It is water cooled engine. I believe it has a mechanical fuel pump. I have changed both fuel filters (no help)I do not believe my dealer and anything he tells me. He said all that was wrong last time was the gasket between the carb half was leaking (4 times in 2 yrs). But when it happened another time I took it to any machanic and he said it started running good by the time he got around to looking at it. It almost sounds like it is hitting the rev limiter, But at idle that can not be happening. It is now running OK at full throttle but will surge when Idling. Need your help.

When you changed the fuel filter(s) did you use the factory (Simplicity or Kawasaki) replacement filters or generic (third party) replacement filters?

Some engines are very picky about fuel filters and their micron ratings and Kawasaki LC twins are very picky.

You should check the fuel tank vent. It will either vent with a hose or a tiny hole in the tank cap.

I used the filter at the Simplicity dealership on both filters. I also have replaced the air filter. This started at least 2 times after I hit a series of very hard bumps.

Halaluha: I found the problem, I am now the head Kawasaki water cooled 20hp surging problem guru. Here's what I found. The main brass jet inside the bowl (you can easily see it once the top of the bowl is off.(watch out don't drop the jet down the intake)(and it's tedious to take out once you unscrew it) It was plugged with stuff. I reamed it out and walla it run perfect. I almost broke my arm slapping myself on the back. I must have stuff in the tank that is getting passed both filters. Anyone with surging motors TRY THIS