I would highly recommend OS engines, especially the new 46 AX or any of the AX series engines. I have five of them, two .75 AX's and three 1.20 AX's and love them all. They start very easily, tune easy, and have a lot of power. My second .75 ran just fine for flight after one tank of break in. I ran it rich, but it ran just fine with plenty of power. It is on a Goldberg Skylark 70, by the way.

CGr