Tractor Repair: ford 3000 quitting, ford 3000, cyl gas

Question
After working tractor under a load for about 35 minutes the 3 cyl. gas engine sputters down and quits. I drained the tank, new fuel filter, battery, coil, points,and condenser.. any ideas??

Answer
  See if there is spark at the spark plugs when the engine dies.  If so, then there is still a fuel problem.  Check that the fuel line to the carburetor is not restricted.  Even though you drained the tank, there could still be a restriction somewhere.  The fuel must run full stream where the fuel line attaches to the carburetor.  A small dribble is not enough to supply it under load.  The petcock valve under the fuel tank is known to plug up easily on these tractors.