Speed Queen Washer model SWT111LA?

I have installed a new belt (ordered from a reputable dealer by model number) on this washer. However when the motor runs it appears the belt is loose and overheats. Question one - it appers that the motor reverses to engage the spin one way, and only to drive the pump the other way, is this correct? Question two - when the motor is engaging the pump only is when the belt overheats. The pulleys are all tight and not worn and the idler pulley also appears ok. What are some common causes for burning up belts?