okay the problem is that i have a hpi savage ss and i have a roto start on it and when i try to start it up it just spins but it doesnt start up. I think that there is a broken tooth in the engine because i checked the rotor start and all of the teeth in it are in good shape so please post some comments to get my tuck runing again..

sounds like your OWB (One Way Bearing) is slipping.

Take your one way bearing out, it is in the roto start piece on the back of the engine and slide it off the shaft and clean it really good with WD-40 or something and pit it back on. WHat you are discribing your one way bearing is shot, cleaning it is just temorary so you might need another one. hope this helps

i dont know if its possible but is the battery plugged in backwards?? if so maby the motor is spinnin backwards too. i personally dont have much experience w the rotostart system but thats the first thing that came to mind.

it could be spinning backwards im not sure i had a tmaxx and got the electric starter on backwards and all it would do is idle but would not go. because a 2-stroke motor can run backwards but not very well. if it not starting at all i have know idea.

sorry if this didnt help

nitro engines cant run backwards because the intake into the crankcase is controlled by a hole cut in the crankshaft, not a reed valve as in larger two stroke engines, so if run backwards the hole in the crank wont line up with the carbie to let fuel and air into the crankcase at the right moment.

actually if it the starter is turning backwards in a rotostart it just spinns the bearing and the engine wont even turn over. making it seem like its slipping constantly.

Ive had my big blocks run backwards before when i put the battery in my starter box in backwards...They will idle running backwards but will flame out the second you give it thottle