HELP! Carb leaks fuel in throat when primed

[Tom hadlow]

Hi all I have a carb from a FS91 that when you primed the carb fuel leaks out in to the throat of the carb. How do I go about fixing this. The strimmer will only run on choke when you give it any throttle it dies but I have also found the valve cover gasket to be leaking and will be replacing it any help and advise is much appreciated thanks Tom