My neighbor lady has this mower and while using the transmission belt broke so the self propelled stopped. I told her I would be glad to replace the belt for her and took it home. I took the covers off and lo and be hold there are 2 bels, a drive belt and transmission belt. You have to take the drive belt off to get the trans belt off which I did put it back together and now when I start it it runs fine, self propels fine and then I shut it off and I can't restart it. It feels like something is keeping mr from pulling the cord fast enough to start the engine. Can any one offer suggestion or tell me what I did wrong!