Hi All, I've a problem child on my hands. A New Way model CH 5HP engine with a Zenith TX4 carb. This carb will not leak a drop when the needle and seat make contact in the float bowl. As soon as it is started the carb drools fuel out of the bottom and it runs rich. All the jets are correct and tight. The float is about as perfect as one can get. Needle and seat work great. Are these carbs that sensitive to vibration? It has a cast iron throttle body. The typical expanding pot metal venturi crack is present and has been dealt with, so that's not an issue. The carb looks good inside. What am I missing here?