Mower deck craftsman lt1000 38" deck wont disengage

I have a 917 287011 lt1000 and when i bought it the blades wont disengage after cutting but were disengaged on starting, now the the belt broke and i bought the 90" belt put it on and the mower will stay engaged always and the clutches are about a 1/2" from the pulleys when disengaged. my question is what size are the idler pulleys i think that someone replaced them with larger ones because one is not painted. for now i will try a 91" to see if that works. but i would love to repair it correctly so if you have any ideas they are greatly welcomed thanks