As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAGNETO PULLED DURING ROUTINE MAINTENANCE TO CHECK FOR THE PRESENCE OF A CHAMPION MANUFACTURED IMPULSE COUPLING. ONE WAS FOUND INSTALLED AND THUS REMOVED FOR REPLACEMENT WITH A NEW ES3163 IMPULSE COUPLING. AFTER REMOVAL OF THE OLD IMPULSE COUPLING, I DISASSEMBLED IT FOR AN INSPECTION AND FOUND THAT BOTH RIVETS HOLDING THE PAWLS IN PLACE WERE LOOSE AND FAILING.