Many push lawn mowers still require a pull cord system to start the engine. Newer lawn mower cords are made of thicker material than their predecessors, making them a bit more durable. Still, one of the most common failures on a lawn mower is the failure of the pull cord. There are several reasons for pull cord failure, including pulling the cord too hard, exposure to the elements or entanglement. Repairing a pull cord is not too difficult.
Remove the screws holding down the housing that contains the starter pulley, and take the casing off the mower. The string pulley is either attached to the housing or left on the mower once the housing is pulled away.
Cut a 9-foot length of cord to wind around the starter pulley. You can trim the length later once you determine how much you need.
Remove the covering of the starter pulley to expose the hole where your rope feeds. You will likely see the broken end of the old rope still inside. Remove it if necessary.
Feed the rope through the open ended side of the starter pulley area, and feed it up through the hole at the bottom of the housing. Pull the rope through the hole with a pair of needle nose pliers. Tie a knot large enough to secure it in place.
Wind the spring loaded section of the housing until the rope begins to wind up with it. Continue winding until you feel the rope begin to bind. Do not force the spring as this will cause it to break. Once it binds, turn it back one full turn.
Run the rope out of the hole of the housing, and put it back onto the mower. Run the rope up through its guides on the mower, and insert it into the pull cord handle.