As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE HAD AN INTERMITTENT DELAYED LIGHTOFF CAUSING HOT STARTS. REPLACING THE IGNITION EXCITER CORRECTED THE PROBLEM. THE DEFECTIVE EXCITER WAS FOUND TO HAVE A LOOSE STUD WHERE THE INPUT VOLTAGE IS APPLIED. SUSPECT THIS WAS CAUSING A LOW OUTPUT VOLTAGE. IT APPEARS THE NUT ON THE STUD WAS OVERTORQUED DURING INSTALLATION, CAUSING THE STUD TO LOOSEN. (K)