The Art of Delivery, fuel'd with questions...?

[tlbuser]

Loss of power with a diesel is 99% of the time fuel related. When it loses power that means the engine is not getting fuel somehow. Whether it's a bad pickup pump, a faulty distributor pump, blocked supply lines, blocked return lines, jacked up injectors or contaminated fuel must be determined before further trouble shooting. If it runs well at first and then starts to act up, you can eliminate the air supply and exhaust questions.
There are tests you can perform if you feel comfortable doing them. It would involve removing the fuel lines one by one from the supply pump then the distributor pump to see if there is air present in the flow. You have to submerge the open end of the line in clean diesel and crank the engine, checking for air. This can be a pain if there are hard lines from the diz pump. Usually it is a good thing to make up a test line that can be fixed to each of the outlet ports of the diz pump being long enough to reach to a jar.
It is most reasonable to assume that the system is sucking air somewhere between the tank and the diz pump, although a faulty injector can't be ruled out. One that works OK when cold but fails as it builds heat will be particularly troublesome to detect.
Diesel shops have sophisticated test equipment to diagnose these kinds of issues. I would suggest that if DIY methods fail to turn up the cause, that you consult a specialist.

Or...you can crack the injector lines one at a time and see what effects what. (before it starts misbehaving)

 

[MichiganIron]

Can't get away from the half full (or half empty depending on personalities) fuel bowl. This sounds like a case of something in the fuel filter assembly. Make sure you completely flush and blow out the fuel filter housing. It sounds like the engine is starving, and from the half empty bowl clue, it's taking it faster than it can get it. Start at the tank, then the fuel filter assembly. The mechanical fuel pump loves a good supply of fuel.

We wouldn't even play with, or photograph, the fuel pump until we could keep the fuel bowl full all the time.

 

[MichiganIron]

One other thing to try before doing anything else.

Run the tractor without the fuel cap tightened. Not the flip up lid, but the screw on cap. It's possible the breather is plugged and you are getting vacuum in the fuel tank.

If that checks, pull the fuel hose at the tank, then as the filter assembly, then at the intake of the fuel pump. See if you can isolate where the obstruction is.

We suspect it is before the fuel filter assembly.

 

[unhappykioti]

Have you checked the fuel cap if it is not venting it can cause draw problems as it does on my 24HP Craftsman. When it starts to run erratically I loosen the fuel cap let some air in and it runs fine. Gotta replace that thing one of these days.

 

[TBDonnelly]

I did take the air gun to the fuel cap, don't know if dirt was dislodged but it did not seem to make any difference.

I think I may have gotten lucky. As wroughtn_harv says, "I'd rather be lucky than good". I made sure I had a replacement fuel pump on site prior to disassembly of the original fuel pump. I went ahead and installed the new pump. Tractor started fine, I let the engine idle for over an hour and a half, setting the throttle at different RPM's. Every thirty minutes I took the tractor out to the compost and moved and flipped the pile with ease and without incident. The fuel bowl stayed full of fuel! So far so good!

The one thing I noted when disassembling the original fuel pump was the six machine screws that hold the pump together were just 'snug'. It took very little pressure on the screwdriver handle to loosen the screws. I expected the screws to be super tight. Perhaps the fuel pump has been sucking air in as it heats up?

If I was good I would have checked those screws prior to dissassembly. Hopefully I've gotten lucky.

I've attached a picture of the new fuel pump installed.

Don

 

[polo1665]

Sounds like you solved your problem. Glad it wasn't too costly for you. Now you can put her back to work

Mark

 

[IslandTractor]

I presume the fuel pump is on the engine side of the fuel bowl. If that is the case than I don't see how a malfunctioning fuel pump could be causing the fuel bowl to half empty. I can envision that a working fuel pump could suck fuel out of the bowl which could be replaced by air if fuel is not freely flowing from the tank into the bowl however. I vote with Michigan Iron. Why don't you put some real strain on the motor (flipping compost is like warm up exercises for a Kioti. Go chase a few Deere around the acres at PTO speed while mowing or tilling) and then see if the problem is solved. If so then maybe blowing out the fuel tank cap was the solution.

 

[TBDonnelly]

I presume the fuel pump is on the engine side of the fuel bowl. If that is the case than I don't see how a malfunctioning fuel pump could be causing the fuel bowl to half empty.

You know what happens when you presume things. The fuel pump is inbetween the fuel tank and the fuel bowl. So the fuel pump is gravity fed from the fuel tank and pumps to the fuel bowl.......fuel passes through the fuel bowl/with filter then forwards in the direction of the engine, so the fuel bowl was really only half full of fuel that comes directly from the fuel pump.

Don

 

[IslandTractor]

You know what happens when you presume things. The fuel pump is inbetween the fuel tank and the fuel bowl. So the fuel pump is gravity fed from the fuel tank and pumps to the fuel bowl.......fuel passes through the fuel bowl/with filter then forwards in the direction of the engine, so the fuel bowl was really only half full of fuel that comes directly from the fuel pump.

Don

I will some day learn not to presume things.

So you are thinking that air was being sucked into the fuel pump and that is how it collects in the fuel bowl? Did you need to refill the bowl every time you lost power or did the problem resolve itself "overnight"?

I still think you need to test out your repair doing something a bit tougher than flipping compost!

 

[TBDonnelly]

I will some day learn not to presume things.

So you are thinking that air was being sucked into the fuel pump after the the engine heated up and expanded the fuel pump housing allowing air to be sucked in and that is how it (the air) collects in the fuel bowl? Did you need to refill the bowl every time you lost power or did the problem resolve itself "overnight"? My thought is the problem resolved itself after the engine would cool down. The fuel pump housing would cool and contract enough to cause a good seal until the next extended use when the engine would heat up enough to cause the pump housing to once again expand and suck air in.

The other unknown is, if there is/was an issue with the fuel hose inbetween the fuel pump and fuel bowl.

I still think you need to test out your repair doing something a bit tougher than flipping compost!

I need to post some pictures of my industrial sized compost pile, it's not for the faint of heart.

Don