[Cub Cadet 1782]

I have a 1782 cub cadet super garden tractor with a kubota d600 Diesel engine and the problem is I have to push the shutdown solenoid in by hand in order to get the tractor to start because it doesn't go in and click when the key is turned like the way it's supposed to. I don't know much about diesel cub cadets so I was wondering if anyone has had this problem before or if anyone had any advice.