Turn the low end out to 1-1/2 open and leave the high at 1 open to start with.I just tried 2 different brand new 11.11mm carbs on my toro25 and it wouldnt idle down hardly at all(i even pulled the idle screw completely out.)It also wouldnt transition right after 1/2 open to wide open throttle.Probably to much carb(brand new engine).Im going down to a 9.53 venturi and trying it.If that doesnt work im going to put on a stock 7.9 with 2 needles(the original had 1 needle.Dont know what hole your talking about unless you mean the atmosperic pressure hole on cover.