Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Welcome to JUST ANSWER small engines, let me try to help you !! The spring loaded idler has to keep the belt tight! To get belt back on track, the idler pulley with spring can be puled back and tied with wire or a small rope. Slip belt on the three pulleys, then release the idler to tension the belt. If the idler spring is missing, then the idler does not keep bet tight. Not a common problem!Is unit still in any warranty? Here is link showing the belt and idler and spring.