I have 13.5 hp craftsman model #917270412 . My son was using the mower and the drive belt broke. I replaced the drive belt, it is on as diagram shows. When the clutch is pushed in ; the belt is loose... when the clutch is let out the belt is tight. The mower will start but dies when I release clutch whether in gear or in neutral. The seat switch is disconnected. If you have any ideas, I would appreciate your input; my grass is growing quickly.