If you remove the squirt nozzle you should find a needle valve in the passage way down the hole. Some have a BB size ball on top of it. Both come out with a magnet. Make sure they are in there. What they do is let the fuel in the passage flow one direction (out the squirt nozzle) when you step on the gas. without them the fuel will bleed back down the passage creating an air pocket in the passage. If they are in there, check the condition of the needle and make sure it's clean and not pitted on the pointed end. A slight easy pump with the needle out will push any dirt or foreign mater out of the passage way.