I'm not familiar with that particular engine, but I got all my engines running perfeclty after reading this forum. The idle mixture sounds rich as stated above. Find it and screw it in out in 1/8 turns (between runs with the engine off so you dont' risk injury), until after idling for 10 or 15 seconds you can push the throttle quickly to full throttle without the engine hesitating. If nothing seems to work, could be an air leak around the carb. I ended up replacing a rubber o-ring from the hardware store for 29 cents.