The injection pump is the high pressure pump that delivers the fuel pressure to the injectors. I believe that you are referencing the transfer pump. The transfer pump has a leaver that runs on a cam lobe and the leaver pulls down on the center of the diaphragm. The external leaver does the same thing. Sometimes there can be wear in the lever mechanism which could restrict the movement of the diaphragm. There are also 2 check valve in the pump. If the diaphragm breaks fuel could leak into the engine crankcase. Usually the check valves either work or they don't. If they don't the transfer pump will not move any fuel. The pump is most likely not serviceable so if it is defective it is replaced complete. If you remove the line from the exit (pressure side) and crank the engine you will be able to tell if the pump is good or not. If there is a lot of fuel flowing then the transfer pump is most likely still good. If there is only a small dribble, with unrestricted feed, there is a possibility that it is defective. The transfer pump should also be able to deliver a small amount of pressure if you block the discharge when the engine is cranking. It is usually 2 or 4 bolts and a gasket holding the transfer pump in place.Given the chorus of counter argument, I have come instead to the determination that the injector pump should be replaced. Thank you for your input.
Reasons the Woodward governor probably not at fault : the engine runs very well, there is very little information on the process of repairing or replacing it, and the noise I was hearing at high RPMs is probably an alternator bearing. So my belief I had broken whatever was causing the noise and therefore the engine was not getting fuel is probably wrong.
It is a fuel supply issue. I thought maybe the injectors needed refurbishment, but the injectors do not exhibit symptoms of fouling and the engine has lots of power. I have been using Seafoam in the fuel since 2012, performed the hot soak yesterday, even though there was a slight improvement in the engine power the RPMs did not go above 2900.
The injector pump has a fabric diaphragm that wears, so is a likely culprit.
Please weigh in if you have experience or information on the injector pump replacement.