The Cessna 120-140 Association Forum

Hi all,

I have a 1947 C140 with a "BOTH" fuel tanks option and a cross over line. I have the original fuel caps with the vent holes in the top. I noticed over the winter that I was using more fuel than I expected, I also notice some streaking down the wing behind the fuel caps.

I suspect that the gasket inside the fuel caps is the culprit and have ordered replacements. I'm still a little suspicious as I would expect fuel siphoning to occur at full tanks however its happening at half tanks as well.

Has anyone experienced siphoning? Was it the gasket or something else?

I've done a thorough inspection of the lines through the cockpit and the gascolator and haven't found any leaks.

Thanks
Marshall

Years ago I left a cap removed, hanging on a chain. About 100 miles into the flight I noticed my level was very low. Landed, fueled up and put it back on. The rest of the flight was normal fuel usage.

Haha, I've seen that on a 172 when I worked the ramp.

Change the gaskets on the caps before you spend a lot of time worrying.