What was found
DURING ROUTINE 100 HR INSP, FOUND NR 3 CYL EXHAUST VALVE STUCK. WHEREBY, PISTON WAS STRIKING VALVE TOO CLOSE. NR1 & NR 3 CYLINDERS AT SEPARATE TIME HAD ON FIRST START OF DRY (COLD) A ROUGH ENGINE AND A BLANK ON MFG EGT SCREEN. WHY CHANGING FUEL INJECTOR NOZZLES FIRST PROBLEM OF ROUGHNESS, DON`T KNOW. USING FLEX BOROSCOPE OF REMAINING CYLINDERS SHOWED THE SAME VALVE MARKS ON NR1, 2 AND 6 PISTONS SHOWING THESE CYLINDER EXHAUST VALVES HAD STUCK PREVIOUSLY. MFGS NOTIFIED OF ISSUE.