I have a 1980 911 SC Targa and I am finding that when I take the fuel cap off to refuel, there is a large amount of air being sucked into the
fuel tank. I assume there is some sort of breather valve somewhere which would normally allow air in and no fuel vapour out? Where exactly
is this? Is it part of the fuelling pipework between the tank and the filler cap? I assume that something is just clogged, where exactly should I be looking? Cheers Murray