Experienced Main Engine unstable running and stoppage due to one unit is not firing satisfactorily. What may be the probable cause of this?
The similar fault was observed due to the hydraulic valve actuator piston rings and cylinders were worn out beyond the acceptable limits. There was no record being maintained of any overhaul carried out on the actuator. The Hydraulic valve actuator must be overhauled as per the Makers recommendations. This prevents knocking of the exhaust valve and improves the performance of the exhaust valve. The piston ring thickness must be checked basis the recommended data given in the instruction manual and plan to mount new rings.