Temp gauge not reading

On the thermometer install, I'm assuming you installed a capilary style temp. probe in the threaded port on the side of the coolant manifold on top the engine? Jeff's right , check the probe in hot water. Boiling water should shoot the gauge right up to ~210 degrees. If you have a gauge with a green/red scale, that would probably be right close to the red.

If your thermostat is inop. & already stuck open, your engine will never heat-up to operating temperature. If you suspect the thermostat may not be working, you can check that by dropping it in a pan of hot water also. The thermo should be closed at room temp, and open ~180 -190 degrees. A candy thermometer in your pot of water helps dial-in the water temp for the test.

George

the words "to Rad" and an arrow are imprinted on the thermostat did you check that?

But before you pull every thing apart, pull out the temp probe and tape the hole, as to not loose too much rad. fluid.

Put the probe in a pot and heat to boiling and see if the guage works. If you have a camp stove you may not even have to remove the gauge from the tractor.

Gauges can be bad too. Check the easy stuff first.