N56ML's header tank sending unit didn't work until I had about fifty hours on the plane...it had stuck to the film that results from the vinylester curing in the tank. Eventually it came lose during some rough air and started working, but even then, I continued to use a calibrated stick to check fuel each time I flew it, and I do the same with 891JF, despite having a totalizer and fuel gauge on it as well.
The reason for this was reinforced when a guy with a C-210 was renting my hangar for a while, and lost 40 gallons of 100LL through a leaking fuel drain valve. I walked in the hangar a few days later and there was no sign or smell of fuel anywhere. So you can park it full (which I usually do also, to minimize water condensation), and still have an empty fuel tank next time you fly. Something to keep in mind. And of course, when you're calibrating your fuel dipstick should be calibrated to show fuel in the flying attitude, despite filling (and checking) it with the tail down (for tail draggers). Mark Langford ML at N56ML.com http://www.n56ml.com
