I have a ys110 mounted in my showtime 90 and i have a question about the engine. When i started it up for the first time yesterday it didnt seem to run right. I opened the high speed needle valve to the recomended staring point of 1 and 1/2 turns and i got it running but not very smoothly. it has an apc 16 x 6 prop, a os type F plug and running cool power 15% heli. I got it running it would run great around 1/3 throttle but as soon as i moved it up near half throttle, it quit. Does this mean it is too rich and suffocating itself on the high end? im scared to lean it out much because i don't want to ruin it.

I anyone has had this engine please share your experience or suggestions about what i should do.