if you had enough pressure in the line to spray some fuel out when you disconnected the line, the carb needle must be working fine - it's a surprise when these old carbs don't leak some where, and if you need a regulator the pump is the problem .... use a good straight edge and check the mating surfaces between the horn and bowl body, it's common the screws have been over-torqued in the last 50 years and things are warped, you might need a better gasket there
Bill
