Gas Walk-Behind Mower: Why won't my lawn mower move?

If the mower moves forward slower than usual, it could be that the drive control cable has stretched out over time. You won't be able to move the drive lever if the cable is too corroded to slide inside its sheath. If the cable is cut, the mower won't move. Replace the cable if you find it damaged or cut.

Your lawn mower won't move with a broken or worn drive belt. Mower drives have a very short mechanical adjustment range for tightening belts, so you can only adjust the belt slightly to tighten the belt. If you adjust a worn belt and it continues to slip, replace the drive belt. Also inspect the drive belt periodically and replace it if it's cracked or the plies are separating; a damaged or worn belt can break and fly off the mower.

The transmission rotates the axle to drive the wheels and move the lawn mower forward. The drive cable pushes the transmission against the drive belt, causing the transmission pulley to spin. Gears inside the transmission rotate the axle when the transmission pulley spins. The mower won't move when the transmission fails. Replace the transmission if it locks up or doesn't rotate the axle to move the lawn mower.

The front deck tray attaches to the front of the mower deck and supports the front wheel axles. On front-wheel drive, self-propelled mowers, the front deck tray holds the transmission. On some self-propelled mowers, the front deck tray anchors the end of the drive control cable. The lawn mower won't move if that cable anchor breaks. Replace the front deck tray if it's damaged or if the cable anchor breaks.

The lawn mower won't move with a broken wheel. A damaged wheel can cause uneven grass cuts. If the wheel on a walk-behind mower is damaged, replace it with one that matches the size on the opposite side of the mower.

If the mower won't move when you engage the drive lever, you may need to adjust the drive belt. Clear debris from the engine pulley and transmission pulley so the belt grips both pulleys firmly when you engage the drive lever. Check the belt guides for correct clearance from the belt when the blade engagement lever is engaged. Adjust the belt guides so the belt properly engages the engine pulley and transmission pulley without belt guide interference.