snapped a screw Injection Pump 2150

That's probably something JD sells as an assembly (the whole pump), if it's available.

IMO, your best bet would be to research the engine make/model (as in, who manufacturered it for JD), and then look through their parts diagrams/service manuals for the engine. And if that does 't work, look for any part numbers/brands on the pump itself, to indicate who makes it and if there are any parts diagrams/service manuals from the original pump manufacturer.

Incidentally, why were you removing that part (it could be either a nut or a bolt)? From what little I know about them (diesel injector pumps), you need to know what your are doing, as some of them have specific setups, where even loosening the wrong bolt will throw the pump off it's calibration, and need fairly specialized tools and/or parts to get it back into calibration, and if you can't do it yourself, the people who have the tools and knowledge tend to want a fair amount of money to do it for you...

If it was just one, and where his finger was pointing was hollow, perhaps, but given that there is a second one with the same style head on the other side of the spring, I would say it's more likely there was/should be a metal wire looped through them in a "do not touch" sort of thing...

But I have pretty limited knowledge about those pumps, so it could be not a big deal (other than the hassle of fixing the broken off bolt/stud).