Replacing the pull cord on a weedeater lawn mower is a relatively simple task that can be completed in just a few minutes. The first step is to remove the spark plug, which can be done by unscrewing it with a wrench. This will prevent the engine from accidentally starting while you are working on it. Next, use a screwdriver to remove the housing cover from the engine. Once the cover is removed, you should be able to see the reel and pulley system. Begin by removing the spring from the reel, and then use a pair of pliers to remove the old pull cord from the pulley. To install the new cord, simply feed it through the eyelet on the reel and attach it to the pulley. Finally, replace the housing cover and screw it into place. Once you have finished, your weedeater lawn mower should be ready to use.