The first Atom edgers had an unbranded Ryobi half-crank engine, while the later ones have a 4 stroke Honda. Be sure you're dealing with the right model before you order a part. The construction of yours seems to be entirely different from the first one (Model 101) though:

https://www.outdoorking-forum.com.au/forum/u...stitch+in+time&Search=true#Post32432