As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) EXHAUST VALVE STUCK OPEN. CYLINDER REMOVED AND REPAIRED IN ENGINE REPAIR FACILITY. REMAINING 3 CYLINDER EXHAUST VALVES CLEANED THROUGH EXHAUST PORT ACCESS. TO BE DETERMINED WHETHER VALVES NEED TO BE REMOVED TO HONE EXHAUST VALVE GUIDE.