ILENGIN, I appreciate the help. I had pulled that plastic valve out on first checking. I had no idea what it was for as I'm ignorant of ICEs. It clearly acted as a one way valve (you call it "rollover"). Found it at Partstree.com. When I suck on the line below the fuel filter, I can draw gas vapor from the tank. However, if I blow on that line, it is definitely shut off. Are you saying I should be able to pass air either way? It acts like a check valve and it can be shaken up and down (makes noise) when pulled out of the tank. So a new one breaths either way unless upside down?