If you ran over a rock or other hard object with your Troy-Bilt riding tractor and now it wonâ€™t start then you may have sheared the flywheel key. If it has been sheared it would need to be replaced.
The flywheel key is a small metal piece that is cut into the crankshaft and flywheel. If the key is broken then the flywheel will rotate out of synch with the crankshaft and the engine will not start. The flywheel key was made as a safety device to protect the engine from more serious damage.
The model and serial number of your Troy-Bilt riding tractor can be found under the seat.
NOTE: if you need a part for the small engine in your Troy-Bilt lawn tractor, there will be a separate model/serial number for the engine. Here are the small engines that are available in your Troy-Bilt tractor. Visit the page of the engine you have to find out where the model/serial number is located for your small engine model: