John Deere 4720 running rough

[Dci]

Hello all,

I have a JD 4720 that has approx. 1100hrs. It has just started running rough when the engine gets a load on it. It acts like it is getting air in the fuel to me. My best description.

I have drained the fuel tank,replaced the fuel filter, and replaced the fuel filter housing/priming pump.

The tractor does not smoke at all during any of the running conditions. You can drive the tractor and it will mostly run fine then lower the box blade and as soon as The governor kicks in it starts running rough. Then you can let off the hydrostatic direction pedal and it will immediately straighten out...

Any ideas on my next step?

Thanks in advance for your time.

Dewayne

 

[thepumpguysc]

Lift/supply pump, not supplying enough fuel to power the load.

 

[Zebrafive]

My first thought was bad fuel, second fuel filter, but looks like you covered those things. Dirty air filter? Final thought is dirty injectors?

 

[kthompson]

Reading the "thepumpguysc" suggestion and what he does would suggest you check that. Hard to beat a pro at his job.

My thoughts you have already covered except the air filter and you are checking it. Had such issue on my JD once and was not getting solid seal with fuel filter gasket.

 

[Dci]

Lift/supply pump, not supplying enough fuel to power the load.

First thank you for your time. Second I知 not 100% sure what pump you are talking about? Would this be the pump right after the tank just before the fuel filter?

 

[ruffdog]

Do you use any Biodiesel that you know of? Is it cold there?

 

[Dci]

Do you use any Biodiesel that you know of? Is it cold there?

Not that I am aware off. The air filter is New as well. I知 in Florida. Thanks

 

[radios1]

Not that I am aware off. The air filter is New as well. I知 in Florida. Thanks

you live in Florida, but, it can still drop to 20F. in the winter there, I personally experienced that, so, how cold was it when this happens?..

 

[thepumpguysc]

Yes, small pump after the tank & before filter

 

[Dci]

Yes, small pump after the tank & before filter

I replaced the small pump and unfortunately no fix..It was 78* today...so fuel is not ice Ing