I have a brand new toro snowblower model 38025 that has a main drive belt that keeps popping off. Thinking the belt was bad I bought and replaced it with a new one and it also slips off. I can't see any misalignment between the 2 pulleys and the idler arm appears to push up against the belt evenly. What else can it be?

Garden - Toro - Ccr Snowblower