You don't say what the other 2 strokes are, but if they are conventional carbs (not air bleed) that may be your problem. Conventional 2 needle carbs turn the same direction for rich/lean adjustment on both HS and LS needles. The air bleed carb LS is the opposite - turn out for lean and in for rich. Your starting point with the air bleed is to set the low end screw so you can see it at half way in the air opening, and you may need to open it (lean) from there.