I have a 80cc engine and the pull starts almost impossible. So I bought a heavy duty pull start and I can get it to start it but the cord rips back in the casing and kills your hand. It's like when the motor starts it doesn't release the pull start it just rips back in and breaks the cord or kills your arm or hand. It worked fine until I had a issue with the small bevel gear on the clutch side key way sheered. So I put another key way in or woodruff key what ever the name is. I used the hand impact driver this time on the screw the holds the little gear on . That worked good now the pull start is acting weird. Any help would be a great.