As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSTALLED NEW M3007 IMPULSE COUPLINGS ON BOTH MAGNETOS. BOTH COUPLINGS CAME OUT OF BOXES DATED 5/25/01. INITIAL OPERATION WAS FINE. IMPULSE COUPLINGS INTERMITTENT SNAPPING. REMOVED MAGNETOS, INSPECTED COUPLINGS PAWLS SHOWED NOTICEABLE WEAR AT CONTACT POINT WITH STRIKER PIN. ALSO LOOSENESS AT PIVOT PIN ATTACH. SUSPECT BAD BATCH OF METAL OR HEAT TREATMENT. INSTALLED NEW IMPULSE COUPLING ASSEMBLIES OPERATIONAL CHECK, FINE. DEFECTIVE IMPULSE COUPLINGS TIME IN SERVICE 93 HOURS/ 119 HOURS