[AL in NY]

Folks, I added a gasket between the idle jet shoulder and the bottom of the upper casting. I does improve the idle mixture sensitivity to the adjustment of the air adjusting screw. The one problem I found is that the space between the idle jet shoulder and the bottom surface of the upper casting varies between .080" and .060". You'll have to use a very small piece of modeling clay to determine your measurement. The Model A/B carburetor gaskets a very hard and don't compress very much, so your measurement has to do fairly accurate. Use gaskets that measure about .005" more then your measured spacing. I think the best solution would be a small .090" thick viton O-ring, because the O-ring will compress to the required thickness.