What was found
RT MAGNETO HAD EXCESSIVE DROP AFTER STARTUP. TRIED CLEARING ENG AND FOUND ENGINE DIED ON THAT MAG. FOUND MAGNETO DISTRIBUTOR GEAR HAD 13 TEETH MISSING (ALL PIECES RECOVERED FROM THE MAG). REASSEMBLED WITH NEW PART. PILOT FLEW ABOUT AN HOUR NO PROBLEMS. NEXT MORNING LT MAG FAILED. FOUND 5 TEETH MISSING (ALL PIECES RECOVERED FROM THE MAG.) BOTH STARTS WERE IN AM WITH AN OVERNIGHT TEMP DOWN TO ABOUT 20 DEG F. POSSIBLE ROTORCRAFT HARMONICS MAY CAUSE THE NYLON GEAR TO HAVE THE CORRECT AMOUNT OF GREASE FROM THE 500 HR INSP. CONFIRMED MAG GEAR HOLDING TOOL (SOMETIMES USED DURING STABBING MAG TO ENGINE) WAS NOT USED OR NOT A CAUSE SINCE THE DAMAGED TEETH CLOCK ANGLE WAS NOT NEAR THE (WINDOW) TIMING TEETH.