As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN MAGNETO WAS UNDERGOING PRELIMINARY INSPECTION, THE CONTACT ASSEMBLY WAS FOUND PITTED AND THE CAM FOLLOWER WAS EXCESSIVELY WORN. SOME CAM FOLLOWER MATERIAL HAD TRANSFERRED TO THE OUTER FELT OF THE CONTACT ASSEMBLY. A THIN DARK COATING WAS FOUND ON THE MAGNETO CAM. CAUSE IS SUSPECTED TO BE CAM FOLLOWER WEAR. CAM FOLLOWER WEAR RESULTS IN DECREASING CONTACT CLEARANCE AND MAY LEAD TO MAGNETO FAILURE.