If you pull them both out, mark the one in the motor that appears to be a problem, put them in a pan and start to boil the water. Watch the good one. If the so-called "bad one" opens the same as the good one, it is for sure NOT a thermostat problem. The raw water motors and the antifreeze coolant motors take a different thermostat, they are NOT the same. I believe the running temp for the raw water version (called the "standard version" by Chris Craft) is a 160-degree device, and the anti-freeze heat exchanger version is hotter.
Tom |