1. Loosen the clutch cable adjuster completely.
2. Confirm there is no tension in the clutch cable at the transmission control arm. If tension exists, disassemble and inspect the Smart Drive control.
3. Inspect the transmission control arm return spring. If the spring is damaged, broken, etc., replace it.
4. Place the mower on a flat level surface and pull it backwards.
5. if it rolls easily, adjust the cable. If it is hard to roll back, the rear adjuster arms should be inspected and cleaned, along with the bushing and axle shaft. Apply general purpose grease to the bushings and axle.
See attached images for details.