Small Engines (Lawn Mowers, etc.): Self-Propelled Craftsman lawnmower, drive wheels, mower deck

Question
I have a 2 yr old variable speed 6.5 hp craftsman lawnmower.
When I first got it, no problem, but now holding the handle
all the way down, the lawn mower barely goes. I do pull the mower backwards in certain mowing positions--self propelled is not engaged.  HELP!  Did I buy a cheap lawnmower?

Answer
Unfortunately the self-propelled systems on most Craftsman mowers require a lot of maintenance.  Common problems are slipping belt or grass clogging up the gears on the drive wheels.

Before doing any trouble shooting, REMOVE the spark plug!
Do not tip the mower on its side or oil will leak out.  Either drain the oil or tilt the mower with the spark plug hole facing up.

Check or replace the belt first.  Then remove the wheels to see if the gears are full of grass/dirt or if the gears are stripped.

Send the mower model number located on the back/rear of the mower deck and I maybe alble to narrow down my response.
Eric