If it's the sh.28 GOOD LUCK. I've had big problems tuning mine. I've spent hours & it still isn't right. To get it to run at all i have to have the bottom way rich turn ir in 1/8 turn & it won't run. Get it were it will run it bogs so bad it almost stalls. It has lots of high rpm power, but if it stalls coming out of turns who cares about top end? Next time i will not buy a RTR so i can pick my own engine.