I changed the mower drive belt on my Weedeater model HD12538J 12.5 HP 38 inch lawn tractor back in June because every time I would try to cut cut grass, the blades just die whenever I hit relatively thick grass. I would like to know how to adjust the idler pulley or whatever adjustment I need to make so that my mower cuts properly.

James Phelps, August 2007

There really is no adjustment but I have had the same problem and it was either a cracked mandrel housing mount or the deck sway bar assembly bracket (part no 130017) that mounts on the chassis. The sway bar bracket had a broken bolt hole and was allowing the deck to move to one side thus reducing the tension on the belt. The mandrel housing mount which has three bolts would tip to one side when the blade drive was engaged. Both of these are relatively easy to repair. The bracket is under $10 or if you replace just the mandrel housing and reuse your shaft and bearings the housing costs under $20. These usually break when you hit an immovable object such as a rock. Hope this helps.

RWF, December 2007