As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PROPELLER WAS LEAKING OIL. HAD OUR SHOP PULL THE PROPELLER AND SEND IT OFF TO BE RE-SEALED. PROP SHOP DISCOVERED THAT THE PISTON HAD WORN OUT OF SPEC. SCORING WAS FOUND ON THE INSIDE OF THE PISTON WHERE IT RIDES ON THE GUIDE. WEAR MARS ARE 180 DEGREES APART ON THE FRONT AND BACK. SEEMS THAT THE PISON WAS COCKED WHILE MOVING ON THE GUIDE ROD. PART REPLACED ANS PROP WAS RE-SEALED