Just bought a used 2003 Hunter 216 - trying to get engine running - It's a 4 stroke yamaha 4 HP engine - I believe the carburator is somewhat gummed up. The fuel intake port on carburator was clogged - got that flushed and working. Changed the fuel filter also. Finally got the engine running, but it won't idle without stalling. Runs fine with at higher gas setting. Any other carburator adjustments or should I admit defeat and take it to shop for thorough carb cleanout?