Okay, so I must admit most of my boat issues are self inflicted....
I arrived at home port, so if things went wrong I would not be stuck in the middle of nowhere. I located my spare thermostat and gasket. I also brought my torch set and spray gasket stuff down to the boat. I put a wrench on bolt number one and applied moderate pressure and the bolt head snapped off. I started up the torch and went around to the front of the engine to heat up the whateveritis that the thermostat housing is attached to. The wire from the sending unit came apart at the terminal fitting. It then crossed my mind that might have led to a bad temp reading and the thermostat was fine.
But since I had one headless bolt, I was committed to removing the housing so tons of heat got two bolts out intact. Another snapped off bolt head. But the housing was off so I put more heat on the whateveritis and with some PB Blaster and some vice grips both studs came out.
So the situation is I am waiting for the new bolts to arrive, I have to check to see if I have something to chase the threads, and I am good to go....... except.....
When I grabbed my torch set I did not grab the striker, so I lit the acetylene with a match before I added some Otwo. Try that sometime and look at all the black smoke. The residue is all over the cabin. I might get killed for this if I don’t find a way to clean this up.