Just put the new rebuild in the boat, thought I was doing everything correct, installed a t stat. I never had a t stat on the motor before the rebuild but I was wanting to do everything by the book. Started up fine in the garage temp stayed at 160*, enjoyed the sound and shut it off. Checked for leaks topped off fluids and restarted, the temp went up to 210* did not come down so I shut if off after about 2 minutes. Took out the T stat which was opened and restarted, temp went down to 170*.
Any thoughts? Do I have to have a t stat?