I had vibration resonate the nose fuel gauge wire down to nearly the bottom once. That was a shock!
(The cork was saturated and nearly ready to sink so it wasn't holding the wire up all that firmly.) As soon as I pulled power back to maximum range, the vibration changed and the cork popped up all the way. Whew! Try taking a scratch pad to the wire of the gauge to smooth out that notch. Don't let the shavings fall inside the tank or stay on the wire. My rule became: I only trust the float gauge when I can see the wire bouncing around. It's good that you are working on calibrating your tank fuel quantities. Well done! Ed Burkhead http://edburkhead.com East Peoria, Illinois ed -at- edburkhead???.com (change -at- to @ and remove "???")
