Having a problem with a YS .91 AC.

When I fire up the motor with the glow stick it is fine. It will idle o.k. with the glow stick on, but once I take it off it will die. I changed out the plug so the plug is not the issue. I think it might be rich or lean but I am not sure. Now if I run it at medium or full throttle no issue. When I pull back the throttle to idle it runs for a few seconds and then stops. If any of you guys can give me some pointers that would be great because this motor is driving me F*&%ing Nuts.

Prop MA 14X8
Fuel Cool Power 20%