As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ACFT PRE-FLIGHT RUN UP FOUND THE MAGNETO WAS UNSERVICEABLE WHEN SWITCHED TO LT ON SWITCH. THE ENGINE WOULD COMPLETELY STOP AND WAS RUNNING ROUGH ON BOTH MAGNETO`S. ENGINE WAS O/H 404 HRS BEFORE WITH NEW MAGNETO`S. UPON FURTHER INVESTIGATION IT WAS FOUND THAT THE DISTRIBUTOR GEAR ASSEMBLY`S ELECTRODE HAD BROKEN FREE AND WAS FLOPPING AROUND NOT DOING ANYTHING.