QUOTE 1. The carb should not fill with the motor turned off regardless of the tank pressure. This is caused from several things. First, at three turns out you are richer than needed ven for break-in. Two, possibly a bad seating of the gasket in the regulator. Three, the regulator might need to be turned in a little bit. Do not be afraid of turning the regulator. Just remember what turns you make.

Then what would cause it? Pressurization is what causes it, if you don't depressurize it then it will flood the carb. Even if there is a rich needle valve, what's pumping the fuel into the carb? That wouldn't be the pressurization would it? Well it is, and unplugging the pressure line, not the fuel line, after every run will depressurize the tank and you won't flood the carb with the fuel.