As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED THAT DURING TAKEOFF ROLL, ENGINE DID NOT SEEM TO BE PRODUCING FULL POWER AND WASN'T REACHING MAX RPM. TAKEOFF ABORTED AND DURING TAXI TO TERMINAL, PILOT PERFORMED MAGNETO CHECK AT LOW RPM. DETERMINED THAT ENGINE WOULD NOT RUN WHEN LT MAGNETO WAS SELECTED ON IGNITION SWITCH. VISUAL INSPECTION DID NOT REVEAL ANY OBVIOUS REASON FOR FAILURE. REPLACEMENT OF LT MAGNETO CORRECTED ISSUE. FAULTY MAGNETO BEING SENT FOR TEAR DOWN INSPECTION AND OVERHAUL.