Belt came off my MTD Bolen 18 HP Kohler engine lawn tractor model 13AX606G565. Put it back on and started fine. It is the longer belt for the blade. Came off second time and put it on and it would not start. Bought new belt and put it on and still will not start. Turn the key and nothing. Charged the Battery and same result. Worked and started fine until the old belt came off the second time.? What would be the problem?