For the last two years I have run my blower motors with thermostats. I figured I needed them since I do not run chokes. I had some idle problems which I traced to the carb idle circuit, few turns problem solved.

This year I left my thermostats out. literally I do not see much difference except my engines stay cooler. RPM and HP is there.

I've heard of other engines not running Thermostats mostly blower motors. What are the pros and cons?

Thanks.

If you are going to run no thermostats you have to have oil temperature guages. The biggest problem on a carbureted boat with no thermostat is too low oil temps. If you run with low oil temp, condensation will not burn off, the oil pump is strained by the thick oil, and you are just waiting to have a lube related problem. If you want to run low water temp you need to think about oil cooler thermostats in order to bring up the oil temp to over 170 degrees-200 is better.

The lower water temp in engine give you more cushion before detonation sets in.