Belarus 250AS runs then quits Power is low?

[videorov]

Tractor cranks up and runs for a little then if put under load it will slowly
stop. Seems to not have much power. Have cleaned and replaced fuel filters
and cleared air from lines. Im not sure if the pump is up to proper pressure.
I haven't checked injector nozzles but maybe they are fine.
Im thinking it might be the fuel pump but don't know.
I have plenty of compresson but not lot of power for some reason.
I have noticed over the past 3 months the power started to go down a bit and
now its to this point of running for a bit and then quits.
Think its the fuel pump? What else could it be?

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[kensfarm]

How about the air filters? Bad fuel?.. maybe drain the tank & rebleed the lines.

[Egon]

Do you have a fuel pump charge pump? Are there any electrical controlled valves in the fuel system? Can you check the fuel pump output pressure?

Think of checking out the entire fuel system again cause that's a lot less pain than a new pump.

Egon

[normde2001]

Could be clogged muffler, or as mentioned before, air filter.

[lwh]

Sounds like a fuel delivery problem. Presuming that fuel tank is full, minimal black smoke is noted under low power, and that this did not start with fuel level low:
1. something is restricting flow or possibly even gasoline in tank instead of diesel. (be certain fuel tank is vented).
2. fuel transfer pump bad (I have zero knowledge of your fuel system, but most diesels have a mechanical or electrical pump to deliver fuel to injection pump. Also vacuum leak here could be problem)
3. bad injection pump

[bgott]

Take the fuel line loose and try blowing back into it. I use my mouth, that way I can feel how much pressure it's taking. You can also take it loose and see how hard it is to get fuel out of the line. If you have a plugged screen in the tank the transfer pump won't be able to move any fuel. Does the tractor smoke badly when it's screwing up? You might have a rubber boot or a air intake line collapsing when you start the tractor. You might want to pull the airfilter housing and intake piping apart and check it thoroughly, it wouldn't be the first time something built a nest in someone's piping.

[chim]

Just for giggles, when the power begins to drop, loosen the fuel cap and see if it makes a difference.....................chim

[DavidJ]

Good one Chim. [img]/forums/images/graemlins/laugh.gif[/img] I had a boat once that the vent got plugged and it would loose power after running a while.

[videorov]

Ive checked all fuel filters and cleaned the oil bath air
filter they all look good now.
I took the lines off the injectors to see how much pressure
in on the lines when I turn the engine over. I put my thumb over the line and can't quit hold it pushing my thumb off.
It has a mechanical fuel pump on the 250AS Belarus.
Thing has me stumped.

[videorov]

Its not smoking very much at all and no white smoke.
It just slowly slows dowm then dies out. I can pump the
fuel pedal but make no diffrence. Ive noticed when I give
it full thottle it doesn't seem to rev up as high as it use to a few months ago. I haven't checked the screen in the fuel tank
Im not sure where that is in there. It has a two stage fuel filter system a coarse and fine filter stage. There might not be one in the tank itself.