Diesel fuelling problems on Perkins 3 cylinder

[Simon_F3]

Hi all, I'm after some advice and/or reassurance please I have a Massey Ferguson MF40 digger with the Perkins 3 cylinder diesel engine, which has run perfectly until the other day. After an hour or so of fairly heavy use it cut out, as if I had pulled the stop lever. Fuel level was low-ish, so I assumed I'd run it out of fuel and put another 20 litres in. It took a bit of effort to re-start (a few squirts of brake cleaner into the intake did the job) but I got it up and running again, only to have the same thing happen about 10 minutes later.
So I got it back to the shed, replaced both fuel filters and cleaned out the glass bowl, and took the top off the injection pump to check the metering valve wasn't gummed up. All seemed good - filters looked fairly clean, gauze at injection pump inlet was clear, inside the pump was reasonably clean but in particular the metering valve was not gummed up and rotated freely in its housing. I gave it a polish with some 800 grit wet and dry anyway, but I'm fairly certain it's working as it should.
It was a pain to bleed through after changing the filters, but the lift pump was definitely doing something and I got as far as getting fuel to the injection pump - though there wasn't much of a spurt from the injection pump bleed screws on cranking.
Anyway, another few squirts of brake cleaner got it going, and it happily idled for an hour or so - but then after about 45 minutes of use it cut out again, identical symptoms to before.
Since then I have replaced the lift pump but not yet tested it other than leaving it idling for a while, and checking it starts again after being stopped (which it does, pretty much on the button).

So my question - do these symptoms (suddenly just stopping, then not restarting without some solvent to get the revs up) suggest it could have been the lift pump all along? It didn't splutter or run on one or two cylinders at all, just cut out like the stop lever was pulled, which made me think it was more likely something in the injection pump sticking when it was warm.

As a side note, I flushed out the tank a year or so ago, and cleaned the gauze filter on the fuel cock, so I'd be surprised if that is blocked. Fuel seemed to be flowing reasonably well from the tank when I changed the lift pump.

I'd be grateful for any comments on this as it's doing my head in!! Many thanks for reading this far

[Billy26F5]

Not an MF expert. I suspect the injector pump and injectors might be in trouble, but what is a very bad thing is to have upset the lapped fit of the metering valve. This now means your pump needs a full overhaul, probably worth doing the injectors too. You might find the governor is in trouble too, butnot the major issue at the moment. The lift pump might have needed a clean, possibly new valves and diaphragm, but you shouldn't have the issues you had from a poor lift pump, unless it was dirty. Never use spray cans in the intake as they will cause addiction preventing the engine from starting without such things. Also worth checking the throttle and stop linkages to ensure they work correctly.
Sandy

[essexpete]

Have you taken out the fuel tap? There might be a gauze on that.
With that breed of MF, as long as the lift pump allows fuel through a full tank and gravity will do the job.

[hair bear]

Two thoughts, is the breather on the tank clear? and is the air cleaner/filter all ok?

[gecko.cx]

Sudden cutout followed easy starting sounds like a collapsing air hose between the filter and manufold.

[Simon_F3]

Hi again all, thanks for the advice and assistance with this. I think I've finally sorted it. I emptied the tank and took off the petcock - the gauze filter had come off (though I think that was probably due to my blowing a bit of compressed air back through the pipe...) so I cleaned everything and fitted a new filter. I blew through the pipe connecting the petcock to the lift pump and nothing significant came out, but on reassembly there was a much better flow to the lift pump so I figured I was on a winner. And lo and behold, on priming and bleeding the injection pump, this time I got loads of air out of the upper bleed screw, and from manual pumping of the lift pump got about a 3ft spurt of diesel from the injection pump which I believe is in the target range Since then it has started easily and run fine, though I've not yet tested it for any length of time. I'm 99% certain that it was just a bit of dirt in the supply to the lift pump as it never bled up as easily as it now does.
Anyway, I thought I'd add a post to close this out, and to say thanks again for the replies.

[hair bear]

Yay!
If you normally have a fairly full tank, there's obviously a greater gravity pressure for feeding, but also any potentially loose stuff in the bottom of the tank remains reasonably inert. Once the level gets down, the sloshing around starts to stir up the bits and they can get in the lift pump valves and beyond (ask me how I know!).
Thanks for the update.