Ken is correct, A section is the narrowest standard-type belt, B section is wider, etc. up through the mega-belts used for heavy equipment. If you have a B section belt on an A section drive, the belt may not be flexible enough to wrap around the smaller diameter pulleys used for A section drives. That would make the belt act as if it is tighter than it is. It would also make it overheat from excessive flexing, and not last all that long. And yes, on that series of numbers, the number after the letter is the belt length in inches. However it is measured around the outside of the belt, not the inside:
http://seekbelts.com/daycobelts/apv-belts.htmlIt sounds as if you have the wrong belt on the clutch drive, and that would be enough to explain the problem you're having. You should be able to adjust the clutch pull-rod satisfactorily with the correct belt in place.
