I tested the sending unit yesterday and found it to be good:
Temp °F / Ohms
55 / 1500
75 / 775
120 / 210
170 / 95
190 / 53
The issue I'm having is the temp gauge reads 120, maybe 130 with a new 142/143 t-stat. Disconnecting the wire it reads 120, while grounding reads 240. I have various resistors ranging from 80-150, so I'll run the gauge through those and compare to sender values to see if it is the gauge.
I also have an IR gun to point at motor but that will have to wait until spring.