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