I have a 1974 Vespa Ciao. I have been trying to get the carb to stop leaking gas out of the top air vent, but I can't figure out what is wrong. I took the carb apart and noticed that there is some liquid inside the plastic float piece. It is not totally full, but almost. However, when I shake it, nothing (no liquid) comes out. Is this liquid supposed to be there, or is there a pinhole somewhere on the float that makes it less bouyant, causing the float needle not to close the inlet valve?