As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED NO DROP IN RPM WHILE PERFORMING MAGNETO CHECK ON GROUND RUN UP. WHILE JIGLING THE KEY AROUND, THE PILOT THEN NOTICED A DROP IN RPM. MAGNETO SWITCH IS CHECKED BEFORE TAKEOFF BY PILOTS FOR PROPER OPERATION AND AT EACH 50 HOUR INSPECTION MY MAINTENANCE.