"Depends entirely on how the engineers designed the carburetor. Carter designed for minimum 0.004~0.006. An additional 0.003-0.004 wear is normal. Remember that 0.010 cold will be less than 0.010 hot."

Jon,

Thanks very much for explaining that. I've put bushings in some of the carburetors I've worked on to minimize the throttle shaft gap "Because I can". After doing that it seemed like the carburetors responded more positively to idle mixture adjustment.

What I've just learned from you is that my perceived "improvement" is probably yet another example of the placebo effect. Or said another way "I wouldn't have seen it if I hadn't believed it".

Ray