Fighting what I think is a fuel issue

kspring61 · Sep 27, 2020

OK, So I have typical symptoms of a fuel issue with one exception. First the symptoms
Tractor bogs down when under a load, going up a hill and/or brush hogging, to the point it will die if I keep pressing it. Even a sharp turn (guessing steering pump load) will bog down the rpm's when brush hogging.
When it starts doing this, if I turn off the PTO and set the throttle to idle, the rpm's fluctuate from 700-1000 rpms for a minute or so and then smooths out at regular idle. I can then make another couple passes brsuh hogging before it starts again.
I have already replaced the fuel filter and air filter.

Here is the exception: When I first start it in the morning and take it out the tractor runs fine, these symptoms don't start showing up for at least 30-45 minutes after running the tractor.
So given this I have ruled out bad fuel
Not sure about a partial plug of the tank because why wouldn't it do this from the get go. It sounds heat related.

One more thing, when it did it this morning I loosened the fuel cap to see if maybe it was vapor locking, that didn't seem to help.

Anything anyone can think of that would cause this to happen after running the tractor for that much time before happening?

This is driving me crazy trying to find this issue

ruffdog · Sep 27, 2020

The engine needs both air and fuel to run. Just quick check your air filter and duct for blockage like a mouse nest.

KWentling · Sep 27, 2020

I would suspect debris in the tank restricting the fuel outlet. Gets sucked to the fuel outlet when the engine is running, floats away when the engine is not running.

oosik · Sep 27, 2020

Runs for 35-45 minuets. I would not suspect anything plugging the air passages. More likely something being drawn into the fuel outlet.

kspring61 · Sep 27, 2020

OK so I went out and ran the tractor some more and same thing, ran great for about an hour and then started acting like it wasn't get enough fuel. Shut it off and sat for a few minutes then started it up and it ran good for another 10-15 minutes and started to bog down. I ran it back to the shop and pulled the fuel line going into the fuel pump and a steady stream of fuel came out of the tank.'
So I pulled the fuel filter, looks brand new just like it should and no small crap in the bowl or anything.

Now I am wondering if when the engine warms up I am not getting air into the fuel system somewhere. I checked the bleeder bolt on the injector pump (Think its the injector pump) and its tight. Checked the #1 and #4 injector nuts on the pump and those are tight. Can't get a wrench on the #2 or #3

Any other ideas?

KWentling · Sep 28, 2020

I'm still thinking it's crap in the tank, but you could rig up a jug of diesel for the pump to suck out of and see if it still does it with a different fuel source.

Egon · Sep 28, 2020

Do you have a fuel line collapsing when it gets hot?

RalphVa · Sep 28, 2020

kspring61 said:
OK, So I have typical symptoms of a fuel issue with one exception. First the symptoms
Tractor bogs down when under a load, going up a hill and/or brush hogging, to the point it will die if I keep pressing it. Even a sharp turn (guessing steering pump load) will bog down the rpm's when brush hogging.
When it starts doing this, if I turn off the PTO and set the throttle to idle, the rpm's fluctuate from 700-1000 rpms for a minute or so and then smooths out at regular idle. I can then make another couple passes brsuh hogging before it starts again.
I have already replaced the fuel filter and air filter.

Here is the exception: When I first start it in the morning and take it out the tractor runs fine, these symptoms don't start showing up for at least 30-45 minutes after running the tractor.
So given this I have ruled out bad fuel
Not sure about a partial plug of the tank because why wouldn't it do this from the get go. It sounds heat related.

One more thing, when it did it this morning I loosened the fuel cap to see if maybe it was vapor locking, that didn't seem to help.

Anything anyone can think of that would cause this to happen after running the tractor for that much time before happening?

This is driving me crazy trying to find this issue

It's a bit early in the year for it to happen, but I had wax globs come out of solution and partly plug the outlet of the fuel tank. It was in the winter, and we had a couple nights below 10 F. Can happen, and fuel service additive won't prevent it, if it's going to happen. It was on a batch of off road diesel that I bought, the only time I'd bought off road. Pretty much same symptoms as you describe. Could be something got dropped into the tank opening that's doing the same thing.

I syphoned the fuel from the tank and then use one of those 3 finger grabber tools to fish out the globs.

Ralph

mrmikey · Sep 28, 2020

I'm still thinking it's crap in the tank, but you could rig up a jug of diesel for the pump to suck out of and see if it still does it with a different fuel source.

What he says.
When I had my Jinma tractor I had the same problem but at a shorter cycle time, 10± minutes or so. Ended up the filter screen that was on the fitting in the end of the tank would collect all the crud in the tank and stop the fuel. Shut it off and it would clear itself 'till the next run session. I ended up draining the tank and removing the intank screen and added a 5/16" see thru in line filter just below the tank outlet.Worked good after that.........Mike

kspring61 · Sep 28, 2020

I have decided when I get back from a trip this week, I am going to do 2 things.
1) drain the tank and then flush it out
2) Take the cover off the fuel pump and make sure there isn't any debris in the diaphragm and it is in good condition. I am assuming this is a diaphragm type pump.