As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSTALLED NEW LEFT AND RIGHT SIDE SLICK (UNISON) MAGNETOS AND IGNITION HARNESS. TEST RUN OK. ON FIRST FLIGHT AFTER 15 MIN. ENGINE POWER LOSS OCCURED. AFTER LANDING FOUND LEFT MAG INOP. REMOVED MAG AND FOUND THAT COIL INSULATION HAD BURNED THROUGH AND HIGH VOLTAGE WAS ARCING TO CASE OF MAG THROUGH COIL INSULATION.