Temp gauge barely moving - sender or gauge ?

[denders]

We have a 1982 mariner with crusader 350's and the starboard temp gauge barely moves. When we are heading out it shows around 100 degrees and the temp on the engine using a temperature gun is 130 - 140. I tried swapping the sender wires from port and starboard , when I did that the issue stayed with the starboard gauge. Is swapping the wire at the engine side sufficient to test the gauge ? or should I really pull both out and swap them at the bridge ?

Thanks in advance

[bud37]

here are some instructions for gage testing.....page 25 or so.....I believe you have proved the sender , but there is a little more to the gage....not much though...

https://fariabeede.com/site_manuals/IS0100q.pdf

[mjk1040]

Swap them at the helm and see what happens.