Based on a couple of pump threads with pix that I've seen the pump is pretty simple inside, but finicky when dirty and obviously wonky if pieces are wrong/missing. Plan to look inside, set engine to TDC on No. 1 and take it and injectors to a shop for inspection...then go from there. This machine was rode hard, messed with, rode harder and finally pushed aside. Still has potential though. Only dead component so far is PTO clutch, which hasn't been pulled and tested yet. Might be a good back-from-dead project yet if engine tests okay.