Lots of guys buy old airplanes from estates. There’s nothing wrong with flying old planes with old engines. In fact, it’s a lot of fun. But you always have to check out your equipment to make sure everything is working properly.
One of the main items on the check list should be the fuel tank. You can usually assume that you’ll have to change the old fuel lines if the plane has been sitting more than ten years. Put some fuel in the tank and see if it leaks. Sometimes there will be nothing but clean oil in your old tank, but frequently the brass lines inside will corrode and leave big particles that will clog your needle valve.
If you unscrew the plug, all too often you will find yourself needing to install a new plug or even a new tank, because the old plug has lost its elasticity. If you don’t feel like messing with this, you can clean out an old tank without disassembling it. Pump some fuel in, shake vigorously, and refer to the following diagram to pump particles and crud out of the tank and into a plastic beverage bottle.
Make sure the weight on the pickup line dangles an inch or two above the bottom of the bottle to avoid picking up garbage and pumping it back into the tank.
Discard the dirty fuel and put a couple more ounces in the tank and do it again until the fuel comes out clean.