Tractor Repair: 585 case forklift, ag tractors, intake hose

Question
I recently purchased a case 585 forklift and am having agonizing problems getting it to run (and stay running). I have had the fuel tank cleaned and coated, the injector pump rebuilt, and all new injectors. It started and seemed to idle great. I then took it out for a test run and it began puking out black smoke and came to a stop. Since then I have been unsuccessful getting it to fire again. I disconnected the lines going to the injectors and tested the flow. It seems to be fine, as it fires a shot from each line in succession. Any ideas on what I can check? It is the older model with on/off munual kill knob. Thanks Ray

Answer
  I normally don't answer questions on industrial equipment (ag tractors only) but this should be fairly easy.  Since you have verified that there is fuel to the injectors, and the fact that it started smoking black tells me that it is not getting enough air.  The air filter may be plugged or there may be a collapsed intake hose. (if it has hoses)