Case 580K rpm reduction during transport

[carlfreeman]

I was moving my tractor between sites in 4th gear. I was on a good road so I was running full speed. After about 4 miles of this the tractor suddenly would not run more than about 1300 rpm. I shifted to 2nd and was able to limp to my destination. All by gauges read in the green and there was no indication (sight, smell, or sound) that anything was wrong. What happened? Is this something a few wrenches and new fuel filter will fix or is it much more involved?

[Gale Hawkins]

New fuel filter would be my next step.

[carlfreeman]

New fuel filter would be my next step.

I replaced the primary and secondary fuel filters. I still have the same problem. It will only rev to 12-1300 rpm. What is my next move? Replace the in-line fuel filter? The fuel pump was rebuilt last March so I don't believe that is my problem, not to say a rebuild can't go bad. Would a hydraulic problem cause this? I have no indication of this, just trying to eliminate possibilities.

[rambler]

90% of these problems are fuel delivery related.

Any plugged fuel filter or screen.

You probably have a screen in the tank, one of my tractors the plastic screen popped off, just a friction fit, and let the fuel line plug up. Unscrew the fuel line in front of the filter, and see if it flows from the line, not dribbles, but flows.

--->Paul

[Gale Hawkins]

I replaced the primary and secondary fuel filters. I still have the same problem. It will only rev to 12-1300 rpm. What is my next move? Replace the in-line fuel filter? The fuel pump was rebuilt last March so I don't believe that is my problem, not to say a rebuild can't go bad. Would a hydraulic problem cause this? I have no indication of this, just trying to eliminate possibilities.

Could have the throttle linkage slipped or something?

[carlfreeman]

I replaced the in-line fuel filter. Status is unchanged. Here is what I have noticed. When the tractor sits overnight it will start and rev up to 3000+ rpm's no problem. After 4-7 minutes (I timed it 3 different times) it will slowly lose revs to previously stated levels. If you shut it off and immediately turn it back on the problem presents itself immediately. This leads me to think that it is not the throttle linkage, I will double check this, but something else. Yes, rambler, it flowed when I pulled off the in-line. Would low hydraulic fluid have anything to do with the engine rev'ing properly?

[gengine]

How's your air filter?

[bcp]

Fuel tank vent plugged? Try it with the filler cap off or loose.

Bruce

[Gale Hawkins]

Fuel tank vent plugged? Try it with the filler cap off or loose.

Bruce

This could be the case but I do not see how it could use enough fuel in four minutes to pull a vacuum to that extent.

I recall an old man many years telling of having a car that would die at the same spot going to work each day. It turned out to be tank trash would gather around the in-tank pick up screen and choke of the flow of fuel. It seemed when the engine would die gas would back flow enough to clean the screen enough for it to start again.

As noted already by another this could be the case here.

[carlfreeman]

Let's throw another variable into the mix. I went back over my receipts and found that my local co-op gave me bio-diesel when they filled up my barrels. I was suprised by this as I did not request bio-diesel. That was about 6 months ago. Does bio-diesel have a shelf life? Are there adverse affects to using bio-diesel? If there are, how do I go about rectifying this? I am going out now to check the air filter and the screen in the fuel tank. Thanks for all your input!