Small Engines (Lawn Mowers, etc.): honda gx340, honda snowthrower, kawasaki motor

Question
Hello i have a Honda snowthrower with the GX340 on it.  It has a surging problem, it will sometimes runs ok on choke but as soon as the choke is taken off it will surge and high or low RPM.  If you turn the throttle down all the way it will die.  I changed the carb cleaned it all out, changed the spark plug and adj. the valves and gov. and still it does the same thing, i did a leak down test on it and it doesn't leak and has good compression and will hold the compression, what else could i try? thanks

Answer
Make sure that you have enough oil in it. It sounds like you have a very powerful motor. The thing it sounds like the most would be the governor clutch inside the crankcase housing...it runs off of the camshaft, and controls the governor arm mechanically. I know someone that had the same problem with his Kawasaki motor on his lawntractor. Make sure that your's isn't broken, which it sounds like it is.