Thermostat on 1970 Evinrude 85hp

[F1shermun]

I took my boat out on the lake this weekend after servicing the lower unit with all new seals and impeller. It ran cool in the driveway. spit water out of the exhaust when you revved it up. When on the lake for a test run it got hot. No water coming out of the two exhaust holes. T-stat is stuck closed. The manual says that it is for maintaining proper water jacket temps and lower unit temps in cold water. Who really boats in the ice? Would it hurt any thing to remove it completely?

 

[R.Johnson]

Re: Thermostat on 1970 Evinrude 85hp

They maintain a warm temp at idle to improve idle performace, and it also helps with low end performance on take off. In some case's if the engine is run without them, it can cause piston scuffing as the cylinder sleeve's are not exspanding properly to maintain piston clearance. This is called cold siezure. They are not the most fun to change, but it must be done.