[RCW]

If you are certain that the governor is not raising the idle by opening the throttle, then it is time to go into the carburetor and remove all the jets and make sure all the passages are open and clear, and quite possibly replace the float needle.

If the float needle looks good, then check the seat that is cast into the carburetor. If it wears it will leak, and is not replaceable.

There is really nothing that will stick in these carburetors, except the float valve. What puzzles me is that if you are getting excess gasoline it should start running rich and trying to flood the engine while the exhaust will smell rich. Since that does not seem to be a problem, there has to be an internal carburetor issue such as a leaky or sticking float valve combined with the pilot screw set incorrectly.

Another possible problem could be the pilot circuit. If you get a chunk of semi-mobile crud in the pilot screw chamber then the starting and idling rpm and first quarter of its power will fluctuate as the junk moves about and either opens the circuit or closes the circuit. It could also be that someone took an air hose to the carburetor and blew out one of the passage blocks (look like little balls). If the latter happens it can sometimes be fixed with a piece of shot being inserted and locked in the open passage, but most often the internal casting on that particular type of carburetor will develop pressure cracks and then the carb is simply shot.