I have one of the 21's converted and I also have one (Still a weed whacker) that my wife claims as her's... They are friendly engines and work very well as a weed whacker. I also have another that is a hedge trimmer. I consider it superior to my Homelite hedge trimmer that is only a 16 cc.

But compared to some of the other weed whacker engines available, the 18 is just too small to overcome the weight penalty of the ignition. My 21 runs a Dynathrust 14-6 at 7000. So you can see it doesn't make it to the ".60" glow engine status.

The reason for all this is apparent when you tear it down and compare the port sizes with those of the Homelite 25, Ryobi 31, Zenoah 23, and many other engines. It is designed as a weed whacker and to be run wide open throttle all day and for this not to hurt it.

Carr Precision advertised in the back of RCM has the back plate mount and hub. The existing muffler is small enough to just gut it and use it as is.

You may be able to find a model that can carry some weight and that doesn't need much power where you can utilize the engine?

Good luck,

Jim