Should of stated what you have TESTED. I'm listening to you so let's roll.
Typical issue is valve lash is out of spec. Would start there first. Next would be hydrolocking. As is pulling the oil stick and smelling for fuel. Next test/check would be poor battery or control cables and connections slash voltage drops.
Now we are onto something. Hot parts means current flow higher than normal. Something is not right here. You need to find out what. What I am reading into is that connection at starter end as you say. Clean, polish and or replace what is needed. This connection shouldn't get hot.
Battery needs load tested. Not talking about putting meter leads on her and reading 12.5 volts. One dead cell and she is all done. Auto parts stores will test for free.