Small Engines (Lawn Mowers, etc.): toro 17-44HXL lawn tractor, snowblower attachment, lawn tractor

Question
I purchased a used toro 17-44hxl lawn tractor with a snowblower attachment.  the belt keeps coming off while using the snowblower.  I purchased a new belt and it still is happening.  Any advice?

Answer
Are the idler pulley bearings and mounting posts in good condition?  Is the engine mounting pulley tight?  Are the engine mounting bolts tight?

Is this your mower model number,71228?

Is this you blower model number,  79966?

I found a lot of manuals for the mower online but the snowblower attachement manual is a little more difficult to find.

Do you still have the snowblower manual?

Eric