toro 20016 won't self propell?

I had the same problem, Remove the plastic belt gaurd for the self propel , there are 2 bolts underneath holding it on. Grind the metal infront of the gear box where it hits the front about 1/4" using a Dremel tool, remove any slack in the cable at the handle if needed. Try it out before putting the plastic gaurd back, grind a little more if needed. This allows the pulley tighten up the belt. Mine works Great now, hope this helps.

Tom B
September 2008