Fuel cap gasket / venting question

[NJMike]

I just bought a Quicksilver Sport 2S. While doing an extensive preflight, I found that the gasket on the inside of the fuel cap was almost half gone. I found some sitting on the lip of the fuel tank also. I removed the residue from the tank lip, and removed the rest of the gasket from the fuel cap.

When I did that, the cap no longer fit snugly onto the fuel tank. The only thing I could find on a Sunday morning was a rubber gasket from Home Depot. That allowed the cap to fit snugly but of course I know I cannot leave it there.

That led me to looking at the manual, which says that "the fuel system is vented through the fuel tank cap". But the fuel cap is solid metal. I didn't see a hole anywhere that would allow it to vent.

The tank is the 12 gal tank that you see on many LSA's.

So I have two questions: 1) where can I get the correct gasket for the fuel cap, and 2) how does the fuel system vent through the fuel cap if there is no hole in it?

Thanks in advance!
Mike

[3Dreaming]

I have seen some metal caps that have a stamped outer shell that vents under the edge of the cap. I used one like this for an aerobatic airplane, but I had to solder the holes shut so it didn't vent.
You might be able to find a gasket that will work at the local auto parts or tractor store. They would likely be better suited for auto fuel.

[NJMike]

True, and I went to the auto parts store immediately. They did not carry the gasket by itself and wanted me to buy the entire gas cap, which I thought was overkill.

[drseti]

The same is true of the oil tank cap used on the Rotax 912. I needed a new gasket (a flat o-ring type), but it was not offered by Lockwood. The entire cap, with gasket, was.

[NJMike]

I just found a "gasket kit" at my local mom & pop hardware store. Three 6"x6" sheets in it - rubber, cork and fiber. I cut one out of fiber.

I'm not sure if rubber is okay or not. Another pilot told me not to use cork.