This is why we keep on telling people to download their parts diagram.
Now you have loosened it you will have to at least tighten it again.
You can add a washer or two to space the pulley further down.
Remember that as the deck raises & lowers the belt run will change.
You can also get a flat idler with a rolled edge ( usually a JD part ) that does not tend to eat belts, I use a lot of them
If the offending pulley is slightly sloped then the bent will run right on the edge as well
