As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PILOT NOTICED A 250 RPM DROP ON THE RIGHT MAGNETO DURING RUN-UP, AS WELL AS SIGNIFICANT ROUGH RUNNING WHEN ONLY THE RIGHT MAGNETO WAS SELECTED. AFTER SHUTDOWN THE RIGHT MAGNETO WAS REMOVED AND DISASSEMBLED. INSPECTION OF THE MAGNETO REVEALED A SHEARED MAGNET SHAFT AT THE WOODRUFF KEY LOCATION.