As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ENGINE RAN ROUGH ON THE GROUND RUN AND WAS SHUTDOWN. THE PILOT FAILED IN HIS ATTEMPT TO RESTART THE ENGINE FOR TROUBLESHOOTING. REMOVAL OF THE MAGNETO REVEALED THE DRIVE TEETH WERE BROKEN. THE MAGNETO WAS REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE.