424 Diesel doesn’t run right

[Semerod Farm]

My 424 diesel has randomly picked up an issue where after about 10-15 minutes of use it will randomly jump like 100-200 or even more rpms and then come right back down or stick for sometimes minutes on end.

It will do this for about half an hour before randomly loosing prime and dying. No coughing or sputtering or slowing down just sudden death and won’t start back up unless you crack the injectors and then the cycle starts right back up again.

Throttle linkage is tight I just replaced fuel filter earlier this year made sure fuel shutoff is coming all the way off. Tractor also has full tank of diesel.

Had the injection pump rebuilt 2 winters ago because the fuel shutoff would not come off unless you got off the tractor and pushed it with a stick.

 

[SadFarmall]

That sounds like ingress of air on the inlet side of the injection pump. I would check the fuel filter first - has it sealed correctly with no fragments of foreign matter against the seal and tightened sufficiently to seal, but so much the seal deforms and allows air in.
SadFarmall

 

[Semerod Farm]

That sounds like ingress of air on the inlet side of the injection pump. I would check the fuel filter first - has it sealed correctly with no fragments of foreign matter against the seal and tightened sufficiently to seal, but so much the seal deforms and allows air in.
SadFarmall

I agree with that but I put the filter on earlier this year and it’s only just started to do this and nothing is leaking but I’ll look closer

 

[JimB2]

Check that there is good flow out of the fuel tank at the input of the lift pump also check the lift pump, the older lift pumps used to have a fine screen to filter the incoming fuel. The screen could be cleaned by removing the top cover off the lift pump.