Glad you figured it out, been using one of those blowers since 2008, never a problem with belts.
Watch out for problems with the two idler pulleys. Snow sits on top of them, when you are finished the bearings are warm and the snow melts and seeps into the bearing eventually taking the bearings out to the tune of approx. $40.00 (Cdn). I made up a couple of shield a few years ago that have ended this problem just a couple of aluminum disks a bit larger than the bearing hub with the outer edge hammer formed down for about 1/16", installed on top of the idler under the retaining nut. Found this information just recently, "Pulley Shields: I ordered 2 of the deck bearing shields for my 44" snowblower idler pulleys and they fit perfectly. They cost $2.06 each with $9 shipping from Green Part Store, well worth it in my opinion. The part # M174222 is correct and was mentioned above." for a more expensive solution that probably doesn't work any better, just JDs answer to a problem. Have heard that new unit may have this installed on them.