I tried to start my craftsman snow thrower model 536.881501. It was turning over but would not start. Tried several times with electric start. Now when I press the electric start it is making a horrible grinding noise and does nothing. What do I do?

The very tip of the starter has a gear called a bendix. It basically acts like a gear sliding down a candy cane groove that allow it to slam into the engine flywheel while it is spinning full tilt. Your gear, frequently plastic or soft metal, has now lost most of its teeth. The gear is plastic or soft metal because it is considered sacrificial and easier and cheaper to replace than a flywheel. Remove the starter and you will see the candycane grooved shaft and a chewed up gear held againist the motor by a spring. Replace the gear with a Sears part. http://www.searspartsdirect.com/partsdirect/brands/Craftsman-Parts In the meantime you should be able to still start it manually but that does not sound like fun since the engine is not starting easily.