these are designed to spin! don't overprop it. 15x8 or 16x6 are good and should give about 8,000 rpm. haven't tried it yet but a smaller prop might even be better. in the echo manual it states that the engine should turn between 9-11K in its original application.

go to the "engine conversions" sub-forum and you'll find many threads about this engine like "don't forget echo!" and "echo on a funtana" lots of info and hop-ups.


dave