When it started were you jumpering to the small "S" terminal on the solenoid or to the solenoid output stud that feeds the starter?
It sounds like you were jumpering around the solenoid direct to the starter, but if so, the solenoid wouldn't have been engaging to engage the starter drive and the stater would have run without cranking the engine, so I don't understand quite what you were doing.
ANYHOW, the solenoid is available separately from DEERE, HE191-1956 @ about $130.00. They want over $500.00 for the damn stater!
You could Give Wetzel's a call and see if he could help you.
Toll Free 1-866-840-2844