I converted one of these 29cc 4 strokes, actually I should say, Ralph Cunningham did most of the work. I tossed the stock carb and experimented with larger walboro carbs. I don’t know what I ended up with but if you are interested I can get that info for you. Oh, I also did get rid of the spark arrestor from the exhaust

The engine with only maybe ¼ gallon through it spins a 18x6 Bolly wood prop at about 6700-6800 rpm, the weight if I remember correctly with ignition and stock muffler after the conversion is about 4lbs. The engine looks promising I was thinking of scratch building a really lofty wing type airplane for it, kind of real basic but just never had the time. I did get a great deal on a Sig rascal 110 from my LHS that I might try this engine in when I get some time.