Troy Built Bronco riding lawnmower, model 13AJ609G766. The extension spring for the idler bracket pulley keeps breaking. Plus the mower speed is slow no matter how hard you press the pedal. I've replaced the spring many times, but it keeps breaking. It looks as though when it's engaged to drive the spring is rubbing against the idler pulley and belt, thus breaking. Any suggestions would be helpful. Thanks.

 

Sounds a bit like both motion drive belts need replacing. Can you see where the pulley is rubbing through the spring? If it was rubbing enough to cut through several springs, I would expect the pulley to be badly worn from the spring too. The belt shouldn't be touching it, but if it did, it wouldn't hurt it much. It would hurt the belt.