The previous belt was fraying some and badly worn. Decided to replace it as well as the mower belt (38" cut). Mower belt was no issues, drive belt on the other hand has been an issue. I removed the worn one and immediately installed the new one, (my idiot proof system) I purchased from NAPA (cross referenceed). After about an 1.5 hours of mowing I noticed a smell, the new belt was coming apart, and appears to have been rubbing. Anyone have any advice, I had already printed out the diagram for both belts before I started, just in case. Does anyone have a photo of the belt installed at the motor pulley and pulleys just downstream?

Hi,
I would avoid the NAPA replacements; many lawn mower belts have a sheath that is not present on aftermarket belts. For some it is obvious because of color, others not so.
Diagram attached. Be sure to check idlers.
Peace,
Clarke