fuel smell
I have fuel smell in my -4 when I top off, actually even when 3/4" below filler neck. It shows up when I level off after takeoff. The outlets (intakes?) from the fuel vents are under the cockpit, and my "air conditioning" naca scoops are under the wings. After a short time the tanks are no longer sloshing the fuel into the vent tube at the top of the tank, and smell goes away. Topoff is the only time this happens, and there are no leaks at the caps. Also no leaks in the cockpit.
The ability to smell fuel venting is rather remarkable. In a 6A that I fly, with bladder buster tanks (bad idea), we had a small leak in a cap at the wingtip, and we could smell fuel in the cockpit. We landed immediately and found no leaks other than the wingtip cap. Blue streak down the wingtip. Hard to imagine that the smell could travel back into the cockpit from the wingtip, but it did.
Jeff
RV4 Toucan