I perhaps originally posted on the wrong forum about this company. They are located in North Carolina and sell converted engines and conversion kits. I am considering building a Ryan's Rebel and wondered if one of these would be reliable on it. Check the links.
http://www.rsengines.net/ryobi/r31kt.html
http://www.rsengines.net/ryobi/ryobi.html

Next question is this. If I bought a used Ryobi 31cc weed eater and removed the engine, bought the kit from RS Engines, could I put it together and install it on the plane, or would I need a bunch of other stuff too?