For the second time since I have owned it, the starter string on my Ryobi multi-attachment trimmer broke. Must be poor design causing too much friction and slowing wearing down the nylon until it frays and breaks.
One of the difficult parts to remove, if you haven’t done it before, is the clutch drum. To do so, you need to remove spark plug and insert a screw driver into the combustion chamber to keep the piston from moving. Then use a Torx 15 driver and insert it into the whole in the front of the drum. Turn the driver counter-clockwise while holding the engine/chassis still to remove the screw holding the drum in place.
After you remove the springs holding the clutch together, loosen the clutch with a wrench and remove it. Then you can remove the gray plastic cover that houses the starter string, pulley, and spring. When you remove the pulley retaining parts, you can lift out the pulley. You need to be careful when doing so because the spring will uncoil all over the place if you don’t reign it in while lifting the pulley out.
I slowly let the spring uncoil so I can work with the pulley. Now you can replace the broken string. The frustrating part for me at this point was keeping the spring in place while trying to attache the pulley. After several failed attempts, I figured out a better way. I was trying to mount the pulley with the string wound around it, which means that the spring has to be uncoiled a bit. But this leads to the spring not wanting to remain flat when the pulley is being mounted on the shaft. The better thing to do is to unwind the the starter string so it is fully extended. You can then wind the spring as tight as it will go around the pulley (less one or two revolutions).
Even though the spring has more potential energy at this point, there is enough friction between each revolution of the spring that it makes it less prone to want to jump off the pulley. I found it much easier to mount the pulley when the spring is wound tighter around it.
I hope this trick will help you if you need to replace the starter string on your Ryobi trimmer.