I bought a used 46" Yardman. I tried replacing drive belts because they were loose. Following all the "expanded" diagrams and what little instruction I could find, I got them on. Same thing again: lower belt loose and won't engage, then smells like it is getting hot. Tractor won't go either. I have checked the belt size, and the front pulley. I noticed also that it looks like the brake/clutch doesn't fully disengage. I think maybe some of the tension springs are not attached or missing or in wrong place. I can't find either a diagram or a picture showing exact placement. It would help it I had the same for the deck.

Are you certain of that model #? It appears you used both upper and lower case letters and may an O instead of a 0