Unless you absolutely want to stick with a four stroke, I have an OS 1.20 AX on mine and it does just fine. It goes vertical at about half to three quarters throttle, take off is at the same throttle. I am using an 15-10 APC, 15% nitro S&W fuel. It starts right up and runs clean all the time with very little fuss after initial startup... slight adjustment of the HS needle for day changes and so on, and that's it for the rest of the day. One flip of the prop starts it right up. A good combination in my opinion.

DS.