Even the best maintained lawn mower will succumb to the dreaded broken pull starter cord. It seems to occur at the most inappropriate time as well. Over time, though, moisture and just plain wear and tear can cause the starter cord to weaken and break inside the starter housing unit. Fortunately, with a few hand tools and about 20 minutes of your time you can repair or replace that broken cord.
Remove the rubber coated spark plug wire from the spark plug. Generally the spark plug is located at the rear of the lawn mower.
Remove the three bolts that hold the starter housing to the lawn mower engine using the 7/16-inch end wrench. On most models there are two bolts on opposite sides of the round housing and one bolt near the spark plug. Typically these bolts are 7/16-inch in size, but other bolt heads maybe used depending on the model of the Briggs and Stratton lawn mower engine.
Remove the housing from the engine. Turn the housing upside down on a flat surface, such as a work table.
Observe the spring tensioned pulley that holds the pull starter cord. There is a single hole in the pulley, which the pull rope will be passed through. Note also that there is another hole in the housing. The pull starter cord will pass through both of these holes.
Wind the spring tension pulley in a clockwise direction, until you can no longer turn it. Align the two holes with each other. You will have to back off of the pulley just a bit in order to align the pulley hole with the one in the housing.
Place one of the hand spring clamps at the 3 o'clock position to hold the pulley to the top of the housing. Secure the other hand spring clamp to the 9 o'clock position on the pulley. This will hold the device in place so you can feed the starter cord through the two holes.
Cut the end of the old starter cord with the cutter on the needle nose pliers. A new starter cord may have the end of the rope already precut. You will need a clean edge so the end of the rope will feed through the two holes. Feed the rope through the housing hole first.
Push the end of the rope into the small hole of the pulley. Grab the end of the rope, through the other side of the pulley hole, with the thin jaws of the needle nose pliers. Pull about 8 inches of the rope through the pulley hole.
Tie a single knot in the end of the rope as near to the end as possible. Pull the rope back through from the housing side, so the knot will rest up against the inside of the pulley.
Release the hand spring clamps and carefully feed the rope through the housing as the spring tension pulley pulls the rope home.
Replace the housing cover to the mower engine. Install the bolts. Secure the spark plug wire back onto the spark plug.