To my thinking, if you are able to crank it by shorting out across the two bolts on the solenoid, that is telling me the starter and solenoid are fine. What is probably happening is that no voltage is coming to that small stud when you turn your key to the start position. You are artificially supplying that voltage when you jump it that way.

Get one of the $ 5 test lights, and touch it to that small post while someone turns the key to start. I bet it doesn't light. Then backtrack and do the same thing on the backside of the ignition switch. I'm betting a bad ignition switch in the start position or a wire from that post on the switch to the post on the solenoid, or your neutral start switch. Now that I reread your post I am thinking neutral start switch.

Don