Tractor Repair: Tractor stalling, rubber hoses, full stream

Question
My father has a LONG 510 tractor that is approximately 20yrs old. He recently had a new fuel injector pump installed. It runs okay but when you put it under a load such as bushogging up a hill it begins to lose power and stalls. Even in 1st gear it will hardly pull itself. You can cut the tractor off and let it set for a couple of minutes, restart and it is fine for about 1 minute then loses power. Have disconnected the air cleaner hose, bypassing the filter, changed primary fuel filter (which was new) with no results. Both fuel filters were changed initially when the injector pump was replaced by local dealer. Any ideas where to check next. Dad is quiet old and for some reason is hesitant to have dealer work on it again.

Thanks

Answer
Hello,

  Check the flow of fuel from the tank.  Disconnect the fuel line where it comes out of the tank and it should run out full stream.  If not, there is a restriction in the fitting on the tank.  It has to run out full stream, a small dribble will not supply enough fuel when the engine is under load.  Also check the fuel line between the tank and the filters for restriction.  Check all fittings and rubber hoses (if there are any) to make sure that no air can be drawn into the fuel before it reaches the injection pump.