Bukh DV10 lift pump

[morgandlm]

Some advice needed please. I have just re-commissioned my old Bukh DV10 after the winter lay-up. One of the winter jobs had included removing the high pressure pipe to the injector (I had renewed the exhaust injection bend) so I knew a thorough bleeding would be required. Despite doing the usual bleed through of diesel and loads of hand and electric cranking, I had the devil of a job to get the engine to run.
The bottom line here is that I am wondering if the fuel lift pump is not working. Access to this is tricky (as are nearly all jobs on this engine) but can it be dismantled in situ? Am I right to think that the engine will work if there is a positive head from the tank even if the lift pump is u/s? I cannot think of why else the engine proved so difficult to start.
Any advice gratefully received.
David Morgan

 

[Bilgediver]

Lift pumps are not good at drawing air through the system. It is bezt practice to give a little help to the fuel so it gets to the discharge coupling of the lift pump ad free of air. Thgis is especially the case if there is a primary filter between the tank and the lift pump.

Some people achieve this with an electric in line pump near the tank and others fit a rubber bulb to pump fuel. I find it easy to pressurise the fuel tank lightly using a dinghy air pump. This helps get the air past the lift pump. It will now work more efficiently.

In answer to your question It depends on the height of the fuel above the lift pump as it still takes a certain pressure to open the spring loaded suction and delivery valves that the fuel has to pass through and this will vary from one pump to another.