As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE RAN VERY ROUGH & RPM DROPPED OFF ON LT MAGNETO DURING MAG CHECK. REMOVED LT MAGNETO. FOUND CONTACT POINT ON MOVEABLE ARM LOOSE & MOVING AROUND DURING POINT OPEN DWELL TIME. ON REMOVING POINTS & OPENING MANUALLY, CONTACT POINT FELL OUT OF ARM. CAPACITOR CHECKED & FOUND TO BE SATISFACTORY. CAUSE FOR FAILURE WAS REPORTED TO BE CONTACT POINT IN MOVEABLE ARM NOT SET PROPERLY.