As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON INITIAL TEST FLIGHT, AFTER INSTALLING ENGINE RECEIVED FROM OVERHAULER, ENGINE HAD UNUSUALLY HIGH CYLINDER HEAD TEMPERATURES AND RAN ROUGH. REMOVED AND REPLACED FUEL SERVEO (PRECISION AIRMOTIVE) WITH SERVICEABLE UNIT AND ENGINE POWER AND TEMPS FOUND NORMAL. FUEL SERVO THAT WAS REMOVED WAS OVERHAULED BY MFG.