Still having starter problems
 

I installed a used starter in my 78 924 that had set for 8 years and it wouldn't turn the engine. I ordered a new starter, installed it and it still won't turn. I have removed the plugs, put oil in the cylinders, and can turn the engine by hand using a socket wrench on the crank. The engine does fill tight, but with a brand new battery, and a new starter, it should do more than just barely turn the engine, and then stop. According to the manual there are 2 resisters in line with the wire from the key switch to the starter and it mentions something about starter boost. I hooked a jumper cable from the negative on the battery to the frame to insure a good ground. Am I missing something here.

Ground the battery to the engine not the frame. I replaced my battery cables and fixed a problem with my starter. It is possible to get a bad rebuilt starter. Easy to take it off and have it tested. Easy to jump the starter solenoid and make sure the starter turns. Good luck