The International Cessna^® 170 Association

My 55B has the vented caps on both fuel tanks. I am used to one tank feeding a little more than the other when both are selected, (which is where I leave the selector all the time) However, yesterday flying around I noticed the right tank showing empty in flight and the left tank showing slightly less than a quarter full. I fueled up full to the top both tanks and the left tank took 9.5 gal and the right took 17 to fill. I have never seen that much difference before. Both tanks were compleatly full at the last fillup. Also the plane sits level in a hanger so that rules out the wing low crossfeed thing. Any thoughts on this matter?

My first thought would be to check the fuel cap vents for a blockage.

Try leveling the plane and checking to see if the ball in the turn and bank is centered. If not center it with the plane leveled, if it is slightly out you will fly with one wing low resulting in a slight flow imbalance between the tanks when flying with the flow selector on both.

The fuel screens at the exit of the tanks may also need cleaning.

This subject has been discussed at length. Here are a couple of such threads:

http://www.cessna170.org/forums/viewtop ... uel#p24083


http://www.cessna170.org/forums/viewtop ... fuel#p9094