Pat, thanks for the suggestions.
Yes I am going to order 2 infrared guns! Sounds like a good thing to have.
I cleaned the heat exchanger in March and the boat sat at Le Phare Blue (Grenada) for 5 months. Also, the temperature gauge read high even at idle RPM. So I think I can exclude the heat exchanger.
No, I did not see steam pushing past the radiator cap. There were a few bubbles of air that came out but the antifreeze was only warm.
Ipanema has still the original Volvo Penta TM22.
Is the rubber ring/gasket the one that looks like a radiator the cap?
I will conduct later on a test of the heat sensor to see how accurate it is and compare the temp with that of an infrared gun.
So, the saga continues
Ipanema SM2K 278