While you wait for answers, we may have found some information which could help you.
Click here for Lawn Mower Drive Belt Repair
Engine runs wide open unless brake pedal is pulled completely back. Why?
transmission oil ?
How do I adjust the tension on a 42 inch yard machine belt ?
adjust variable mechanism -- how/??
rebuilding a lawnmower engine?
How do I tighten the drive cable on a yard machine snow blower?