With the solenoid disconnected, you can also check for continuity between one of the leads and the solenoid case. There should be no continuity.
With everything installed, my solenoid does get a little warm. After about 2 minutes, the solenoid is around 105 -110 degrees. The tractor and air temperature was about 80 degrees.
Also, the spec on the solenoid is 1.5 amps.
If all of this checks ok, the next check would probably be the solenoid valve.