Hi everyone! I still have the boat home doing maintenance things. When I run the boat with the hose muffs on the temp gauge stays at 100 with the engine running. After I run it for 5-10 mins it still says 100. I turn the key off and back to the on position without starting the engine and it shoots up between 150 and 170. If I start the boat the temp gauge moves to 100. Why does the gauge only read when the engine is off with key in the on position? Thanks for your time!