JD 440A runs good until it warms up then it spits and spiders then quits

[Rick Love]

Any ideas what the problem might be. It runs so good until it warms up!

[thecfarm]

After it warms up?
It's at idle and then you try to drive it?

[rusticretreater]

It is likely you have a problem with your fuel system.  A gasoline engine needs three things to run.  Fuel, compression and spark.  A diesel engine doesn't have a spark, you do have compression as the engine does run, therefore your problem is with the fuel system.

Check fuel flow.  The usual stuff, fuel filter, fuel pump.  When its warm, pull the bleeder plug before the injector pump and turn the key on and see how your fuel flow is.  If you can find a factory service manual it should have some information on what the flow rate should be.

It is possible that the return line is not working properly.  If the fuel gets too hot it can boil causing vapor lock.

[East ky logging]

If it starts back up alright after it has set for several hours it sounds like the check valve on the fuel return side is stopping up. It is right on top of the injection pump where the return line goes into. It just looks like a fitting but it has a ball and spring that sometimes get crud in it that will cause problems. 

[Nemologger]

Put new fuel filters on it and blow the fuel line back toward the tank

[cuznguido]

And if none of those things help, make sure the fuel tank vent is clear.

[newoodguy78]

All good suggestions above. One other thing to check is there any sort of filter/screen in the tank where the supply originates from?  I've had issues with this in the past. Was just enough crud in the tank it would run for awhile then sputter out once it plugged the screen. 

[Gearbox]

If you don't solve it quickly put a marine plastic tank up by the winch. 440s were famous for broken pick up tubes and rust in the tank . It's a major job  to pull the tank . I think you have to split the  machine  

[BurkettvilleBob]

More then likely it's a fuel issue as has been mentioned, if it has the rectangular glass fuel filter it should be easy to tell if it's running out of fuel. I seem to remember that mine would stall if the differential lock was left on for a long time, first you'd lose steering and then I think the engine would stall.

[Kodiakmac]

Check electrical leads/connections to fuel pump.  Years ago I had problems with the engine cutting out when the skidder was put in motion.  That was the issue.  I had spent countless frustrating hours looking at every other possibility, and then it turned out to be something so simple.