If the float bowls are full then the bubble is probably not a big deal. If the bowls were empty, they should fill up and you shouldn't see a bubble in the fuel line. If the bowls were empty and you're seeing the bubble then the float needle might be stuck not allowing fuel to flow.Dirtbag said:When I put the tank back on and open up the fuel lines, should the lines fill right up with fuel? I have a huge air bubble in the closest line. If they should be full of fuel what do I need to do?