As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(YN8R) UPON PERFORMING ENGINE RUN-UP, ENGINE PERFORMANCE NOTED UNSATISFACTORY. PROBLEM ISOLOATED BY MX TO BE SEVERELY RETARDED TIMING VALUES ON BOTH MAGNETOS. SUSPECT BROKEN OR MIS ASSEMBLED IMPULSE COUPLING SPRINGS IN BOTH MAGNETOS. AWAITING TEAR-DOWN REPORT FOR DETAILS. PARTS UNDER WARRANTY AND UNABLE TO DISASSEMBLE PRIOR TO RETURNING TO MFG. BOTH MAGS SAME PN, MAGNETO SN'S: D08JA296 AND D08JA286