Running Hotter Now

[Nibor]

Hi all. I just ran up my engine yesterday and it ran at 190. It has always run at 160. I opened up the engine bay and it seemed as always. I could put my hand on it for a short time and the coolant reservoir was cool. I think it is just the gauge. Lots of water out the back as well. A little background. It is in a sailboat and is a Universal MB20 22 HP. The gauges , except for the tach , work on and off. I am trying to figure that one out. Also , we just went through two months of below zero weather. I had a heater on the boat but did not open the engine compartment. I did not think it necessary. Maybe the thermostat or temp sender got damaged in the cold? Any thoughts? Thank you in advance.