Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Welcome to JUST ANSWER small engines, let me try to help you !! I don't know it all, but maybe together we can get you a satisfactory answer!
Be sure the end covers are in place, and any belt guides are close enough to the pulleys to keep belt from coming out. Belt guides need to be close enough to the pulleys , that the belt can't be removed until guides are loosened. If the idler and the center pulley does not have guides, make guides ath will bolt to the center bolt/nut and come out and lip over the pulley to keep belt on. Just needs to a strap of metal, with a 90 degree angle bent on it and a hole drilled for the bolt. These do have lots of complaints, and adding belt guides will help.
something lie this, made from flat stock.
I see question open, did you come up with a solution?