Mercruiser 200/Crusader 185

[homemade87]

Originally Posted by Ghost1972

I've changed Alpha one impellers before. And I run 89 or 90 Octane (ethanol free if I can get it). Because it's a closed cooled system, the raw water from the heat exchanger goes to the exhaust. So I want to keep the raw water below 140. I bought Motorad High performance 160 and 180 thermostats to test. Probably go with the 160. The engine has been running rich, and the temperature has been around 150.

I have found that the boat gauges are not that accurate . If you put the 160 in and run it that way I would take note at what the temp gauges says and use it for a reference . Dont take the gauge as what actual temp it is . I have never had one dead on . If I see the gauge jump 15 or 20 degrees or more I know its time to start looking for a problem . If not I dont worry about it .