MAIN ENGINE FUEL PUMP DISCHARGE PIPE SEATING :
In D/Dock M/E (Akasaka UET) the fuel valves of two units (Out of 6 units), changed with O/hauled ones (PMS) by S/staff and T/Charger complete o/haul was done by shore w/shop. V/L came out of D/Dock and during the passage, when the engine speed was raised from maneuvering full speed to sea speed, observed T/C surging.
The replaced fuel valves were removed, after stopping the engine, pressure tested. Found satisfactory and refitted same on to the units. No other work was done on M.E. Workshop was consulted and T/C (not again removed) as workshop confirmed that it was in order.
Engine was run again but T/C hunting persisted. After about 3 days of investigation, finally suspected the high pressure fuel pipe between fuel pump and fuel valve of both units, same opened up and found bore diameter reduced from about 8 mm to 4.5mm at the conical seats. Same restored to correct size, and then engine was run and found surging had stopped and we could increase the speed.
Lesson learnt :
Whenever main engine or auxiliary engine fuel valves are changed, it is better to inspect and clean the bore of the high pressure pipe and also to rectify any defects noticed at the tip.
M.Natarajan Batch - 45