I have a 1994 model 2160ags. It only has 175 hours on it. The starter went bad. I replaced it and it ran fine. It cut off one day while mowing an incline. When I tried to restart, i could hear the starter engage, but the engine would not crank. I took the started back off and noticed that I could not move the flywheel at all. It is locked, and will not move. I even tried a few light raps with a hammer on the back of a large screwdriver. It is solid. Any hope? Any suggestions?