Originally Posted by
cub builder
If you only have the main and header tank, the GlasAir only has one main tank that spans across the wings. Whichever wing is downhill is going to want to overflow. Leave the caps on and check it again on a level surface. The tanks should level out again and should also equalize once you taxi onto the runway to take off.
If you have the tip tanks installed, they have some rather complicated antisiphon and anti-overflow plumbing between the tips and the main tank. If the tip tank is overflowing, the valving that controls that is mounted just under the seam where the tip tank attaches to the wing. The tip tanks should feed into the mains during flight automatically if the valving is all working correctly.
However, since I don't know your specific plane's configuration, please put the plane on level ground and check that the fuel tanks level out again.