I wouldn't mess with the tank. The most I would do is to get one of those oil drain pumps, put some kero in there and suck it all back out otherwise I'd just leave it alone. From what you are saying, you have natural fuel flow from every hose right? Pull the line directly at the fuel tank that leads to the filter and blow it out just to be sure. Do the same thing from the filter to the injector nozzle hard lines. maybe you can get lucky and blow out a wad of wax plug. The last thing you want to do is replace an injector pump. Do not forget, these need to be aligned perfectly to time with the engine.
The cost of these things is silly. Almost $500 for a used one for one of these but under a hundred bucks for the larger JD tractors of even older vintage. A rebuilt would probably cost you $650. If Fredericks or Hoye has rebuild parts, let them rebuild your core and be aware of how to properly take down the original pump and put it back as a result of it needing timing alignment.
I loved my JD 750. But parts became so cantankerous to acquire, I simply traded it for a new tractor. If I broke the steering yoke which was a cast piece, it would have cost $450 for a used one. I had already broken the knuckle so the yoke was a possibility. This could end up costing you just under a grand if you are messing with injectors, pump and hard line so do as little as you need to get this machine running.
I just do not have the patience to start jumping through hoops for parts so much so, that I gladly paid the 10K difference to acquire the new machine.
I applaud your perseverance and patience mainly because I have so little.
