Pull the wire from the spark plug by grasping the boot and pulling it off. Remove the retaining screws from the engine cover using a Phillips screwdriver. Pull the cover off the engine. Turn the cover over and remove the old starter cord from the pulley if it is still there.
Spin the pulley until you begin to feel the spring tighten. Insert the end of the starter cord into the opening and tie a knot at the end to secure it. Insert the other end of the cord through the cover opening and pull it all the way through. Install the handle on the end of the cord and tie a knot to secure it.
Allow the pulley to retract slowly and wind the starter cord onto it. Put the cover on the snowblower engine and install the retaining screws using a Phillips screwdriver. Plug the wire onto the spark plug. Pull the cord out of the housing several times to check that it will rewind properly after each start.