Dave,
Let's find out if your solenoid works.

Install two jumper wires. One on the positive battery post and the other on the negative. Remove all wires going to the small terminals on the solenoid. Then, carefully touch one jumper wire to each of the small terminals on the solenoid. It does not matter which way you do it because the solenoid is not polarity sensitive. If the engine spins over when you do this, then the solenoid is OK.

Remove the jumper wires from the battery.

Use a test light or multimeter on the DC scale to check whether 12 volts is being delivered to the end of the wire that is coming from the ignition switch and is supposed to go to the small terminal on the solenoid. Don't forget... you have to turn the key to START to make this test. If you don't have 12 volts there, then you have to make sure that the ignition switch is actually getting 12 volts delivered to it. The fuse is the logical thing to check next and that includes the fuse holder as well. If you can access the "B" terminal on the ignition switch, then you should see 12 volts there.

If you do have 12 volts at the "B" terminal but do not get 12 volts delivered to the starter solenoid, then you need a new ignition switch. That MUST come from an Ingersoll dealer in order to get the correct one. Do not waste your time trying to source it locally. Use this link. Case, Colt and Ingersoll Garden Tractor Parts Bob will ship you a new one either the same or next day depending how fast you contact him. Make sure to tell him the model number and serial number of your tractor.

Any auto store will have a test probe for a few bucks. These look like a screwdriver but with a pointed blade and a clear handle that has a wire coming out the top and an alligator clip on the end. Just place the alligator clip on the negative battery post and use the pointed end on any spot you expect to find 12 volts. If the voltage is there, the handle will light up.

Thanks for the greeting but as a Canadian, I celebrated Turkey Day back in October. LOL