While flying my Archer a couple nights ago, there was a strong odor of avgas in the cockpit. After returning to the airport, I carefully inspected the interior of the aircraft particularly around the fuel selector/shutoff valve. Finding nothing, I checked the wing root and crawled under the fuselage to look for any blue fuel stains. I found the tell-tale stains on the cowl in the vicinity of the gascolator. On closer inspection I found the gascolator had a small leak where the bowl contacts the rubber gasket. After removing and inspecting the gasket, the bowl was put back in place, the mounting screw/nut was tightened an extra quarter turn and the unit safety wired. The problem seems to be fixed. I left the cabin and baggage doors open to "air out" the cabin. Should be good to go.
Amazing how such a small leak can contaminate the cabin air. I am sure the problem resulted from repeated fuel samples being taken during preflight. The quick drain is mounted on the bottom of the gascolator bowl so pressure on the drain valve stresses the rubber gasket (compressing the back side and easing pressure on the front side). The leak was on the front side.
Tonight I decided to seal and set the five internal tank ribs in the skins. I am following an alternate procedure for sealing the tanks that has been discussed at great length on the Van's Air Force website. That is, set the prosealed ribs into the skin and cleco 100%. I will let the sealant setup a day or two and then drive the rivets wet. While there will no doubt be a little mess when driving the rivets, getting the sealed ribs into the skin was relatively clean.
I am still not excited about working with proseal and will be glad when the tanks are complete. I sure hope they are leak free!
