Has the carb worked weel before and then all of a sudden started thisor did you change pumps?

If it worked before then all of a sudden started it almost has to be in the needle and seat area. check the O-rings around the seat barrel to see if they are letting fuel bypass the seat. check the seat to see if the neoprene point is bad, or if there is a nick if it is brass. check the float for saturation or full of fuel if it is hollow brass.

my 2c worth.
John