Well, if you can, remove the fuelline from the carb while the engine is at an idle.If you can't, then try and pinch it with a pair of needle nose. Listen to the rpms as the engine quits. If the rpms increase as the engine quits, Low end is to rich. If rpms just go down and quit, too lean. Iset all my engines for a very slight increaee andthey have all run flawlessly for years-----including my 1 year old 2300 (inverted to boot).