Thanks guys. Trouble shot it today using hot cooking oil heated up to 200. Got nothing on the gauge. Grounded out the sensor wire and it went full hot. That told me it was the sensor. Picked up a new one and all is good now. Temp is still only about 190 but it’s cold water the boat normally does not see.

Got a pic of the part number Incase anyone needs it from advanced auto.

That’s a cool fitting Rookie, was not aware it existed.