On my 4.3L mercruiser (1994?) my temp gauge does not work correctly. The gauge does not move even when it the motor is up to operating temperature. When I ground the wire off the sender the gauge needle moves to full hot suggesting the gauge is ok. I am going to remove the sender and check it. in some water on the stove. How can I tell if my thermostat is opening correctly without removing it? I would think even if the thermostat is not opening correctly I should get some reading on the gauge. Maybe a the sender threads have corrosion and not grounding. Any tips would be helpful. How many ohms should I read at 140 degrees?
