Then, you've got engine troubles; more than likely low compression, since the engine was stuck. That is to say, the engine may now be free but perhaps all of the rings aren't.
If this were my tractor, I shoot a can of GM's Top Engine Cleaner in the intake while cranking it over. Slop it down real good and let it soak overnight to see if the thing loosens up enough to at least get it started.
Also, do you have good engine cranking speed? No, ya can't pull 'em to start.
Another thought; perhaps you're up against the original reason it was parked to start with?
Just thinkin' out loud here,