[Healeys] Temp gauge 30 degrees off - why?

[Steve B. Gerow]

Hello listers,

Last weekend I adjusted my temp gauge pointer - it was showing 30+ degrees hot. 

I removed the thermostat and fan belt and inserted a cooking thermometer of known accuracy next to the temp gauge pickup bulb. Then removed the needle from the gauge and ran the engine to 190 degrees re-attaching the needle at 190 indicated. This appears to have worked properly.

Does anyone know how the gauge gets out of adjustment, especially that far?

-- 
Steve Gerow
Altadena, CA
BN6