Disclaimer-I am not a mechanic, just someone that did not want to be out done by replacing a cord. I removed the screws from the bottom of the unit to separate mechanism that held the blades from the engine. This revealed a clutch on the end of the drive shaft. I removed the springs so I could remove the two halves of the centrifical clutch. I did this so I could then remove the mount these two halves were around. This mount had an arrow and the word 'off' on it. I placed a block of wood against this mount and hit the wood (protecting the mount) as to spin off the mount in the direction of the arrow. A few sharp licks with the hammer and the mount started to come off. I removed it by hand then. Next I removed screws and spark plug so I could get the green housing off where the cord was mounted. Inside this housing is a white spool the cord was on. Becareful with the next step. To replace the cord I removed the spool the cord is wound on but be careful, under the spool is a metal housing under which is the spring that rewinds the cord when you pull start the unit. The end of the white spool that is out of your sight meshes with the end rewind spring. If you pull too far up on the spring or the metal housing that keeps the spring in place you will have spring everywhere and possibly toward your face becareful. So Loosen the two screws and turn the tabs out of the way that hold down the white cord spool. Slowly work the white cord spool off. Replace the cord on the spool making sure you wind it in the proper direction. Then replace the spool and mesh it with the spring. Turn the spool to wind the spring and retention the pull cord rewinding spring. re assemble unit. Good luck! This is not a step by step but I believe it will get you what you need.
Record-ed in Carolina, March 2007
