A quote from BS Skinner's book: "The most common error in centering the jet is doing the whole bit with the jet slightly down from the lean position and so you are not on the fattest part of the needle and your setting is inaccurate." I have the Moss centering tool which works great. I think I have the jet as far as it will go.How can I be sure I have the jet cranked up all the way when the spring hides the threads?