How to Repair a Mower's Spinning Flywheel

Park the mower and cut off the engine. Open the front hood to access the engine. The flywheel is the large wheel-shaped iron part at the top of the engine assembly.

Remove the bolts from the flywheel cover with a socket wrench. Use your hands to pry off the cover and expose the flywheel.

Use a hand file to remove any burrs on the outer fins of the flywheel. Set the flywheel's cover back into place and reinsert its bolts using the socket wrench.

Test the mower. The burrs may have been the flywheel's only issue.

Remove the flywheel's cover in the same manner as before if the mower still is not working. The flywheel is likely not spinning and must be entirely replaced. Position a flywheel pulley over the exposed flywheel so the pulley's two arms lower down directly against the outside of the flywheel.

Use the socket wrench to tighten the pulley's center bolt. This tightening will create pressure on the flywheel. Tighten the bolt until the pressure forces the flywheel to pop loose from the engine block.

Position the new, replacement flywheel into the space occupied by the old flywheel. Insert the center bolt of the flywheel directly into the center of the flywheel. Use the socket wrench to tighten it into place with clockwise twists.

Slide the flywheel's cover over the top of the new flywheel. Bolt it down with the socket wrench and the previously removed bolts.