Undo the four screws holding the starter cover to the side of the chainsaw. Take the screws out and lift the cover up to pull it away. Flip the cover over to change the pull string.
Pull the spring clip out of the center of the pulley with the needle-nosed pliers. Lift the string rotor, with washer and pawl, off the starter cover. Cut the rope off the starter handle and the knot at the base of the pulley.
Insert the new string through the hole in the center of the handle. Tie a knot at the end of the string. Push the knot into the center of the handle. Thread the string through the starter cover and the center of the rotor. Tie another knot at the other end of the string.
Place a finger tip's worth of engine grease on the string's rotor bearings, in the center of the rotor. Put the rotor back onto the starter post. Twist the rotor back and forth to hook it onto the recoil spring.
Refit the starter pawl and washer into the center of the rotor if they were removed. Press the spring clip back through the starter post. Make sure the spring clip points clockwise.
Form a loop in the unwound string. Pull the loop and turn the rotor six full revolutions clockwise. Press down on the rotor. Untwist the string. Take your thumb off the rotor slowly to allow the string to rewind onto the rotor. Refit the starter cover to the engine.