[AL in NY]

Folks, I am talking about the UPPER carburetor casting fit to the wide shoulder of the idle jet, not the threaded tapered fitting in the lower casting. There is a chamber in the upper casting where fuel is mixed with air before being drawn into the carburetor throat. This chamber should only receive air through the idle air adjustment needle valve. The fit of the idle jet into the upper casting is a loose sliding fit which would allow air to be drawn into the mixing chamber, bypassing the idle air adjustment needle valve. I wanted to know if anyone had tried adding a gasket to the wide shoulder of the idle jet to prevent this air leak. Preventing this air leak would increase the sensitivity of air adjustments made at the needle valve. This question/modification is directed at the B carburetor, I was assuming the A carburetor was similarly built.