I just bought an '01 Country Clipper Zeton with 200 hours on it. Everything is in fine shape except the engine surges. Runs smooth under load but with the PTO off the engine speed hunts--at all rpms. Sometimes it settles down, sometimes not. Engine is a FH721V (seems to be a very popular engine). I've cleaned the carb exterior, checked linkages & sprayed cleaner inside. I haven't removed the carb because the muffler is in the way so that's a last resort. Air filter & plugs are new. I pried off the pilot screw caps & tried to richen the mixture but that didn't seem to help--but I may not be doing it right. The Kaw engine service manual doesn't have any adjustment procedure(!!). Might this problem go away if I throw a bottle of Techron in the tank or am I gonna need to take it apart further? BTW whats the factory pilot screw setting?