You need to screw the high speed needle out some. In orther words,after you peak the engine out for maximam rpm, open the high needle back up two or three clicks.

Pick up the model and hold the nose straight up and see what it does. Try it in all attitudes on the ground and see f it quits.

The bottom line is that you are trying to run the engine too fast. The Irvine is one of the best engines you can buy.

Enjoy,

Jim