As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER A LANDING AND COOLDOWN THE PILOT PRESSED THE START/DETENT SWITCH TO MOVE THE TWIST GRIP TO CUTOFF. THE ENGINE IMMEDIATELY FLAMED OUT WHEN THE SWITCH WAS DEPRESSED (TWIST GRIP WAS NOT TURNED). THEN ATTEMPTED TO RECREATE THIS PROBLEM AND IT HAPPENED AT ALL ENGINE SPEEDS. AFTER TROUBLESHOOTING IT WAS DETERMINED THAT THE P3 PRESSURE SWITCH WAS THE PROBLEM.