carburetor weeps around top

Hi, Original W1 model 331S carburetor on my 36T. It's been rebuilt -runs perfectly and has good idle, good acceleration, etc. The float is set at about 7/16 to 1/2" which I believe is lower than the spec; it has a new needle and seat, but it is NOS, not the newer viton type. The stock fuel pump puts out around 4-5 PSI. Every time the engine is shut off, fuel weeps around the top gasket perimeter. It doesn't continue to weep - it's just long enough to dampen the upper portion of the carb. Ideas?