9-12-09 why won't my mower self propel? Also ,mower is a rear wheel drive so back wheels are not supposed to go backwards but they do now. The motor is a briggs and straton and cranks with no trouble any help is appreciated. THANKS

Hi,
You will need to remove the rear wheels to inspect the drive system. It may be the wheels have the gearing stripped on them. That would be the most common thing.
Manual is here:
http://dl.owneriq.net/5/5f8fa8f2-c4ff-4d51-89dd-5f82df9736b2.pdf
Peace,
Clarke