Working on a 763 with a replacement motor of unknown origin. The motor has great compression (425 +/- 5 on all cylinders) and starts without glow plugs at 30 degrees F. We did have the injection pump rebuilt by a reputable shop. That is what made it start great. It ramps up to speed and runs well. The problem is after 5-10 minutes it just shuts down. It is not an electrical problem we can hold the solenoid open on the fuel shutoff. We've bypassed the lift pump and are using a 5 psi electric pump. That is working even when it quits and we can open the bypass screw to the injection pump and see fuel drain. We have screwed with the governor springs only because we pulled the injection pump. But we purchased new ones and think it is correct. It does ramp up to speed OK. I have not 100% verfied that there isn't water in the fuel but we do have a filter in place. I also can't 100% confirm what is happening with fuel when it shuts down. We did put in a clear paper fuel filter and see fuel when it is shutting down in the filter. Is there any simple thing/test I'm not doing?