[Drewboy]

For Hellosailer and others - I agree that the engine is running too cold. The thermostat and sender are both new and tested. The temp gauge is also good and I'm able to check temp with an infrared thermometer.

Based on a thought read elsewhere I made a run yesterday with the raw water intake seacock partially closed and guess what? The temperature went up and I could get it to the recommended range. I believe this worked because the thermostat bypass amount is too great and that lets colder raw water in from the start, never letting the engine heat up. Partially closing the seacock limits the bypass amount.

Any way to adjust the amount of bypass in the thermostat?