I have a Zama carb on a 32 cc craftsman weed wacker that has stopped running. when I pump the primer bulb fuel flows out of the carb venturi instead of going back out the over flow tube and back into the tank. I have taken the carb apart but there is really nothing in there to look at. any ideas? At this point i'm thinking about just buying a new carb, they cost around 32 delivered and for that price no one is gonna open up my carb and look at and fix it.