Just picked up a case 500. It has not run for 5+ years but always parked inside. We were able to prime the system and lift pump seems to be supplying fuel but there is no high pressure to the injectors. Looking inside the timing cover the pump seems to be clean as a whistle. My guess is that the plunger may be stuck.Is there any tricks to free it up? We have not yet pulled the hydraulic head as we thought that maybe just having fuel to the pump may help. I have only ever worked on an ih pump so do not know much about these. One thing i am wondering is whether the gear inside the timing cover should rotate or is that just to afjust the timing of the pump. Any help appreciated.