Ford Lehman 2715E CAV Minimec Injector Pump - Fuel in Oil

[CaptainBob]

We've got an ongoing issue with air getting into our fuel system when the engine is sat un-used. Have replaced and re-seated everything multiple times.

Decided it must almost certainly be caused by air entering at the injector pump. Also found today that fuel is getting into the separate oil sump our Minimec injector pump has.

I've changed the oil in the pump and will monitor the level closely until we're lifted out at the end of the month.

Do you think this fuel in the oil issue could indeed also be the source of air in the fuel?

Do you think it's OK to run the engine with this known issue. We're away from our home port at the moment and need to get back to our usual yard for lift-out.

Any recommendations for someone to remove and refurb the injector pump in the Totnes area?

TY!

 

[LittleShip]

Those injector pumps are known to let fuel into the sump of the pump. It is recommended to change the oil every 50hrs.

Air in system..... Could be from anywhere but as you have redone the fittings it is "possible" that the pump is the problem.

Rebuild in Totnes ...... Can't help with that.

Running the engine with fuel getting into the pump isn't going to be a problem short term, with the usual caveat of your the one looking at it.

Check the fuel lift pump diaphragm on the engine, that could be the cause of the air leak.

Good luck with this one.

Tom.

 

[CaptainBob]

Hi LS. Thanks for your reply.

I changed the engine lift pump a few engine hours ago, but found the fuel entering the main engine sump was from the return fuel rail itself, not from one of the return line banjos. More info here: http://www.yacht-forum.co.uk/viewtopic.php?t=692 I seem to recall you'd installed copper washers on your banjos to stop this issue but I found mine was definitely from the rail as per pics in link.

Back to my fuel in injector pump... I checked back through my log and found it's actually 111 hours on the engine since I last checked/changed the injector oil. I'd estimate there was a total of about 200ml excess in there. Do you reckon 100ml of fuel every 55.5 hours is within the normal operating range for this pump - which has been going for 35 years to date?

I also had a thought - if the level is rising in the injector pump, won't the pressure of the air above the oil in there be increasing? Could that then be forcing air into the fuel at the last bleed screw - especially after a long run of the engine? Those are my exact symptoms.

 

[LittleShip]

if the level is rising in the injector pump, won't the pressure of the air above the oil in there be increasing?

That's one of the common problems with the fuel pump, one work around to this is to drill a very small hole in the filler plug. Personally I haven't done that but I do know many of the Grand Banks owners with Ford engines have done so.

We're you getting air in the pump before you changed the lift pump. ???

Tom.

 

[Paragon]

I don't know how well you know Totnes, but if you know young Steve the marine engineer then he would certainly be able to help, PM me if you need numbers etc. I know who I certainly wouldn't recommend in the locality too!

 

[Paragon]

Also had another thought, he has some pressure gizmo for checking fuel systems for air leaks so may be able to eliminate that too, really nice guy as well

 

[CaptainBob]

Ooh so perhaps this is an ok level of leak then? And it might be the source of air? V excited my air saga could be over.

Lift pump was dripping fuel before. I had multiple problems so hard to know if one thing caused another.

Steve of marine wise? Yes know him. Nice chap. Will talk to him when we get back.

Thank you!