When you say, " There is power going to the starter but no power goinjg to the solenoid" I don't understand this sentence, and it's probably going to confuse other electrical guys, too. "
A solenoid is just an on/off switch powered by electricity instead of a manual knob or lever. The key switch sends voltage to the starter solenoid which then sends full power on to the starter motor and it cranks the engine.
So power to the starter has to get there by going through the starter solenoid. There isn't any power to the starter motor until the solenoid sends power there. There is always power to one side of the starter solenoid - which is usually mounted on or next to the starter. When the key switch activates the starter solenoid switch it closes (with a click) and sends cranking power on to the starter motor. That cranks the engine. It may not start, but it will crank over i.e. turn over normally. If it doesn't crank, there is your problem .... either the key switch, the starter solenoid, or the starter motor is not getting voltage, and in that order.
There is another solenoid on some models that opens the fuel flow from the tank to the fuel pump. If your tractor cranks normally but doesn't start you need to check that one too.
My guess is it is a safety switch. Mine has two on the drivers seat, one on the clutch pedal, and one on the PTO.
A bad battery cable or connector to battery or frame will also allow all the electrics to work EXCEPT the starter motor.
That is very common, and if you have a new battery that probably means the cables and connectors need renewing too.
rScotty