Here is how I do it:
- After I build the tanks I let them sit on the bench for a few weeks with a 5-10 gallons of 100LL in it. I rotate the tanks to different position from time to time. The objectives are to find any weeping rivets and to flush the tank. I drain the fuel via a hose connected to the sump through a see through auto fuel filter back into 5 gal jugs. This is repeated until I'm sure no junk in the tank.
- With the tanks on the wings, wings mounted and fuel system plumbed, I replace the AirFlow Performce fuel filter with another see through auto filter. I disconnect the fuel line on the engine side of the firewall and connect a hose to a a five gallon tank.
- With the tanks empty, proceed with your EFIS or EMS fuel level calibration proceedure (most do a 2 gallon at a time add to each tank).
- After you hit the top of the fuel sender travel, use the planes fuel pump to pump each tank to the series of 5 gallon jugs. Measure the fuel flow and convert to GPH.
This process calibrates the fuel level senders, flushes the fuel system, and verifies the pump can deliver much more than the engine can use.
Carl