OK

I pulled the #$%^ starter out, and hooked it up to good battery. I hooked up negative to the frame, and positive to the large terminal on the starter. Then I used a screwdriver to short the large terminal to the small terminal on the starter. I heard the click, and the starter motor spun into life.

I also tried hooking positive directly to the lead that goes from the solenoid into the starter. I got an even bigger spark, and once again the starter motor spun.

Now I am severely confused. Why would it work when it is not connected to the engine? Does this test prove the starter is functioning properly??? Or could it just be too weak to spin when hooked up to a heavy load like my engine???

I was gonna go pick up a new starter this afternoon, but now I'm not so sure.

Clean the bettery terminals and check for corrosion. Starters require lots of amps to turn the motor. If that doesn't work,

While a friend attempts a to start the jeep, lightly tap the starter with a hammer to try to unstick the solenoid. If that doesn't work

Throw in a new starter and if it doesn't work you may not be getting enough current to the starter because of a bad wire

Check the + and - wires from the battery to the starter. There may be a fracture in the wire which means high resistance and low amps getting to the starter. Using an ohmmeter check resistance. Resistance should be almost 0 thru those 4 guage battery wires. Isolate where the high resistance is along the wire. My neg battery wire had a fracture caused by a kink right as the wire connected to the terminal. If that doesn't work

It may be the ignition. Check the ignition relay underhood in the fuse box. Beyond that, I dunno