Semi OT, Perkins diesel help

[hoof]

Hello all, My MF tractor, (Use to move machines) has developed a problem. It starts fine and runs for five or so minutes. It's RPM's start to taper off over this time period. Then it dies. However it will start back up in just a few seconds. And repeats again and agian. I have done what I think is most of the basics. Changed the filter, boost pump, fuel, cleaned the tank etc. What I did observe is after it shuts down the top bleeder on the injector pump bleeds air, The lower one does not. The appears to be no leakes in the line, (No wet spot anyways). And the injector pump is also dry. How does this air get in there, and how do I keep it from happening again?. I could sure use this thing right about now, A go figure as fate would have it it's not running very good. Over the coures of years as I was just playing with it it never failed me.

Kind regards

Ray

[chuckinnc]

My MF1135 done the same thing it turned out to be a bad fuel pump, mine
has a manual lever under the fuel pump that you can manually pump/bleed
the system if you run it out of diesel. I thought the fuel pump was good because I cound pump it and it would start again, then I noticed if I would
keep pumping it it would stay running. Must have been something in the
mechanical linkage/arm that runs off the engine.

[becksmachine]

Check to see if there is a strainer internally in the fuel tank. On mine the only way to check is to unscrew it from the bottom of the tank, it is attached to the fitting that screws into the bottom of the tank.

Obviously a messy operation, even after draining as much as you can from the tank. Usually compounded by the fact that you just filled the tank to make sure that wasn't the problem.

Dave

[Mike Burdick]

hoof,

You've probably eliminated this already but...

Could the engine shut off valve be slowly vibrating back and then killing the engine?

[lynnl]

Now this idea is probably WAAAy out in left field, but I'll toss it in anyway.

Years ago I had a nice little Homelite weed trimmer that ran great, until the 3rd or 4th year, then it starting displaying similar symptoms. I figured I couldn't hurt anything, so decided to tear into it. What I found (only after I'd taken it completely apart) was dirt-dobbers/daubers (???) had partially clogged up the muffler/exhaust system.
Cleaned it out and it ran fine.
A year or so later, same scenario, except I knew where to look this time.

Not suggesting you have a dirt dauber problem, but if all else seems ok, you might check to see if your exhaust system is free and clear.

[Willy]

You will be looking for an air leak on the lift or suction side of the fuel system.

Not as easy to find as a fuel leak as these are very hard to find since they leave no telltale signs of leakage. A regular fuel line leak will weep or drip fuel, whereas a fuel line that allows the ingress of air usually will not show any signs that it is allowing air in.
The usual suspects are anywhere that the fuel line has fittings, clamps, or shows signs of physical distress.

Be thorough and vigilant in your search, leave nothing to chance start at one end and continue to the other until you are satisfied that the fuel delivery circuit will hold a vacuum for 15 min. A handheld pump is handy for this procedure, plug one end of the lift circuit and apply 10" of vacuum, it should hold steady. Hopefully you will find it without having to resort to this last step.

[Bill McLeod]

I'll second the vacuum leak is there another filter like an add in Racor on the lift side? I would put a small electric pump on the fuel intake line preferrably right at the tank end pressurize the whole fuel line as what Willy said about finding a vacuum leak is difficult so switch the whole system to pressure and look for the leak. Everything else you did was on my go to firsts list.

[DannyW]

My MF 165 had symptoms of clogged filters or tank strainer clogging.
It stalled a couple of times, and when it did it could only be started after the lines were bled free of air.

Turned out to be a valve in the fuel pump (not injection pump) that was loose and fell out of its seating. The telltale was that the diesel in the sight glass dropped in level and was full of air bubbles.

As to your problem ... I have no clue, other than as above, an air leak on the lift or suction side of the fuel system.
But the leak must be very close to the injection pump, because you can start it back up again without much difficulty.

Why it does restart in your case is what boggles me.

Let us know what you find!

Danny

[hoof]

As Willey ans Bill McLoed pointed out it is most likely an air leak not showing up as a wet spot of fuel. I'm coming up short as to how to deliver fusl under pressure though. I wonder if a gravity feed fuel system would work just to troubleshoot? If so what kind of head pressure would I need? 5 feet 10,15 ??? Gravity is something on do have on hand. A pump however would be a bit harder at the moment. I saw a guy on TV use a turkey baster to fix a truck one time ? McGuivuer or the like. A pnumatic cylinder ? I'll give some of the like a try and let you all know what I find out. Again Thanks

Ray

[Bill McLeod]

I'm a boat guy not a tractor guy but i have put a outboard motor day tank on the roof of a truck when the fuel pump was broken so I guess a gravity feed would work but a pressure pump will be faster and definite. If you go with gravity I would hook it up and leave it over night. Automoive suppliers have generic electric pumps, with one some fuel line hose and clamps it should show up