Hmmm...finally a question I feel qualified to answer. I have the same carburetor and had the same problem. The paper gasket that comes with the rebuild kit doesn't seal well. For a good seal, get some cork/rubber gasket material from your parts store. As I recall, the package said it was recommended for exposure to fuel. Use the paper gasket in the kit as a template to cut a new gasket from the cork. Tighten the 4 screws that hold the metal retainer on the glass bowl carefully and evenly (the manual suggests 1/4 turn increments). Do not tighten those screws too much or you can warp the casting (trust me on that one). I find it easier to do this with the carb off and the bowl face up, but I have done it in place too--you just have to make sure the gasket stays in place, especially under the float where it's hard to see. If you haven't done it already, you should download the manual for that carb from www.oldcarprojectmanual.com . It will tell you everything you need to know about your carb.