Trying to understand how the cooling circuit works...can't seem to find the right information. When running at lower rpm e.g. 1500 the engine temp comes up to around 140F but when running at higher rpm e.g. 2500 the engine temp indicator plummets to the lowest level which is about 100F. Since the river water is 45F I suspect the engine temp drops lower. I'm sure the bypass valve is opening to cause this temp drop. How is the cooling system supposed to work to maintain a reasonable operating temperature when there is a bypass valve that seems to void the temp control provided by the thermostat? I appreciate a response from anyone who can explain how this is supposed to work.