Let's back up for a minute and look at one thing at a time. You are blowing a ten amp fuse when you try to start. Unplug the solenoid you have in place now and try to start. Does the fuse still blow? IF so the problem with the fuse blowing is not related to the new solenoid, as it is out of the circuit for this test.Dave - Thanks for your help ! I just received the new fuel solenoid and installed it. That didn't fix the issue. I also put a new seat safety switch in as well. Tried starting with power to new solenoid and with power disconnected. With power to new solenoid it cranks and blows a 10A fuse immediately. With power disconnected from solenoid it cranks but won't start, but does not blow fuse. Do you think the solenoid relay could be the culprit?
Then look at the solenoid armature. Is it fully extended? If so, you may have the wrong part. Look at the old solenoid. Can you move the armature in by pushing on it, or pull it out by pulling on it? From the sounds of it, it is likely your solenoid should have the armature retracted, and it should extend on shutdown, for a short time, and then return to the retracted position by spring action. (I say this because you report that the tractor will start when the solenoid is removed.)
Did you check any of these things? If you got a solenoid that works opposite to the original your tractor will not start. BUT the wrong solenoid would likely not blow the 10 amp fuse. But it might if it is a totally wrong part.
If you are going to fix the problem, using logical trouble shooting steps to zero in on the root cause of your problem will be helpful.
Sure, the relay that activates the fuel shutoff solenoid could be a problem. As could a shorted wire somewhere in the circuit. But something does not sound right, unless the wiring diagram that was posted is not accurate for your tractor...Usually there is one root cause for a problem. BUT there could be two issues going on. Life is strange sometimes...
You CAN fix this if you just work through it step by step...