I have aSears rider with 42" cut and the mower will not disengage. It is a mower with a lever that you push up and lock in place to engage the mower. There is a cable on the lever with a spring on the end of it that is hooked to the mower deck. When I pull on it, the mower disengages. Is it possible the cable/spring assembly needs replacing?
Mower is about 8 years old and is used extensively. Any help would be appreciated.

Sounds the pulleys are stuck
Remove the deck and clean it off and see if the pulley moves back and forth that the cable hooks to.
Luck