Outdoor Power Equipment, Small Engine, Lawn Mower Repairs, Troubleshooting and Safety


Flywheel Position at Top Dead Center

The following photos show the position of the flywheel magnet relative to the ignition module with piston at top dead center (tdc) and flywheel key intact. They may be useful in determining if the flywheel key is sheared when the keyways are not visible without removing the flywheel. Typically the trailing edge of the flywheel magnet will be very near the forward edge of the ignition module. All these photos should be considered approximate. Top dead center was determined by touching a screwdriver to the face of the piston and rotating the flywheel to the position where the screwdriver was extended out the spark plug hole by the maximum amount.