Help w/ Testing Temp Guage

[Murphy8166]

My boat is running a little warm (190 to 200) after changing impeller, thermostat and temp sending unit of manifold and checking all connections for blockage. Also pulled the circulation pump to confirm it was in good condition.

Can someone please advise me how to electrically check to make sure the wiring and the gauge are not the culprit.

1.) How do I test the connection b/t the sending unit and the gauge?

2.) How do I check to make sure the gauge is accurate?

3.) How do I make sure that I don't have a short or a bad ground.

I do have a multimeter and a test wire with alligator clips.

Also, the reason i want to test the gauge is that the upper heat exchangers never get to the point where I can keep my hand on them for at least 5 seconds. I also have an infrared thermo gun and I can shoot the thermostat area and it reads around 160 which is the setting of the thermostat.

Thanks

[electricjohn]

Dipping the sender in a liquid of known temperature (while still connected to its source) is how I do instrument calibration. You just have to figure out how to keep the sender grounded.