Temp gauge

I have some trouble with my temp-readings (water)
New thermostat, new sender, flushed radiator, new gauge (sunpro)
The gauge shows up to 230 farenheit. But i dont think the engine is that warm. I allso feel the temp rises too quickly, is 180 within short time.
When i measure the sender with an ohm-meter it goes from 140-120 ohm when its warm.(230 on gauge)
Someone here who can tell me what these ohm-readings means in farenheit?
Frode L
Norway



