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Lister LD1 - Fuel pump issue

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Stevenbolster:
I've been de-carbonising the Lister LD1 out of my boat, following the guidance in the handbook.  Everything has gone reasonably well, with everything back together with new head gasket etc.

I'm at the stage of bleeding the fuel system  and trying to get it running.  All good to the feed pipe where it goes into the injector, confirming fuel squirting as the crank is turned.  I connected it to the injector and got injector 'creak'. Great!  Went for a start but after about half a dozen turns the creak stopped.  Disconnected the feed pipe and no 'squirt'.

 The handbook says to remove the delivery valve holder and spring, lift the valve and allow fuel to flow.  Then put it back together.  Simple. Unfortunately it doesn't mention the little 'plunger'-type component with a slotted head, which sits inside the spring.  Neither does this appear in the exploded diagram of the pump.  Unfortunately, when I removed it I didn't pay attention to which way up it goes.  i.e. does the 'plunger' go on top of the spring, with the slot upper-most, inside the holder; or does the slotted face go downward, directly onto the top of the valve.    I've tried it both ways, and without the plunger altogether.  On each occasion the result is the same, - fuel squirts from the injector feed pipe for about half-a-dozen cycles of the pump, then ceases.

The fuel tank is about 8 inches above the level of the injector so pressure to the pump should be good.  Its fresh diesel and a new filter.  The injector was serviced by a specialist injector company. 

Any adive or guidance would be appreciated.  I've attached a photo of the 'plunger', and the exploded diagram.

mike90045:

i've found air bubbles in the fuel filter, and they were difficult to get out.  Same symptom, fired a couple times, then air.

With all creak's you mention, is it firing at all ?  Sometimes the vibration will help shake air bubbles loose.

Often diesel fuel filters have a bleeder screw on them to help purge air.

cobbadog:
I too would be looking for more air in the line and filter housing. Fortunately on my filter housing there is a bleed screw on both inlet and outlet on the top of the housing. I only bled the outlet side. Then follw your line along bleeding at each joint and then the outlet of the pump / rack then where it connects to the injector.

With the assembly of the pump/rack I think the way you have it as an exploded view aorks for me. You can see the marks from the spring on the shaft of the part with the slot.

If necessary put 2-3 psi of compressed air into the top of your fuel tank, this will also aid in shifting air out.

Willw:
Hi Stevenbolster, the 'plunger' goes on top of the spring, with the slot upper-most, inside the holder, the lower end of the spring fits over the end of the delivery valve.

Stevenbolster:
Thanks.  That makes a certain amount of sense.  Do you happen to know what its function is?  It confused me that it is not shown in the manufacturer's exploded diagram of the pump, or the list of parts.

I suspect my fundamental problem is still air in the fuel feed.  I'll just have to persist with the bleeding.

Thanks again.

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