Small Engines (Lawn Mowers, etc.): starter on troy built riding mower, starters, plastic gear

Question
what makes the flywheel turn about 1/16th of a turn and stop.I repalced starter with new starter drive gear which is metal instead of plastic gear.Is there a shim that goes on starter to keep starter drive gear from binding against flywheel.I didnt see one when i took the old starter off the mower.

Answer
These starters are not shimmed like an automotive starter can be. I would wonder if you have a bad ground or some other connection issue. The other thing I wonder is if your valves have been adjusted. If not, you may want to have them adjusted and then try to start it.