Lift Pump – 6BTA Leaking on plunger when priming

[Stephen Oliver]

Hi Guys

6BTA 330 Diamonds. Just finished redoing the whole fuel hoses and filtration on the boat. Primed the SB engine with a combination of bulb and lift pump (I’ll get an electric primer next time!) Engine ran but stuttered a bit and then smoothed off.. great.

Went to the Port engine released the secondary filter to get the fuel moving (I didnt prefill as I didnt have any clean diesel) once diesel was present I started pumping with a fair bit of resistance to the bulb, so moved onto the lift pump, pressed the plunger and air and diesel spurted out of the plunger.. kept pumping and all i could hear was air.. back to the bulb, built up some pressure then back to the lift pump and same again.. as soon as I pressed the plunger, air hissed out and then diesel. I managed to get the engine running and no sign of diesel leaking when running..

I’m assuming the lift pump plunger has knackered seals? If so what are the options? Overhaul or just a new one? – Typically its the port motor so access is dire to put it mildly! One good thing is I have remote last chances and am redoing the pipework to and from them.. so they have to come off anyway!

Steve

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[Stephen Oliver]

Thanks Tony

Is this a common thing? It seems to seal ok when running and stationary.. just when pumping. I’ll have an investigation into what’s involved in the removal etc and see when I can fit the job in.. it may be something I leave for a bit. I’d be interested to know if you do strip one what is involved..

Steve

[Tony Athens]

New pump or try and rebuild– That is your call…………………….. Might be a simple as a new $1 o-ring. I do know the priming part of the pump is separate from the main lift pump (like two separate pumps) .

Never taken one apart with the intention of a seal repair, but maybe I will for when we finish a ZF220 clutch repair late next week… Kinda curious myself..

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