Sub question: I have a 1967 M20F Executive 21, JPI EDM 900, CiES senders, 64 gallon wet tank. Between the installation manual and this thread I got the procedure down on how to drain, fill and calibrate. Thanks to all. The current fuel level calibration is many gallons off. Indicates 5 and mechanical float gauge on wing shows 11-13 which is very close. Fuel flow is perfect. So for now.... does anyone have the set calibration numbers for a like model to share? The 1/4, 1/2, 3/4, and full values that seem successful. Each plane installation is difference and should be a custom set-up, which I will in about 64 gallon of time. It's so far off now it can't get any worse really.