Cut a clear plastic bottle down to a 4- to 6-inch cup. Wash it out thoroughly.
Unwind a coat hanger, or remove the pen cartridge from a ballpoint pen.
Hold the clear plastic cup under the aircraft test nozzles (under the wings typically or under the propeller cowling). Push the tip of the ballpoint pen or wire into the valve. Release approximately 1 inch of fuel into the cup, and inspect for sediment or water.
Screw the cap onto the threaded end of the clear plumbing tube.
Cut a piece of wire from a coat hanger 1 inch longer than the length of the plastic tube piece.
Drill a small hole in the center of the cap, on the inside of the tube. Do not go all the way through; just make it deep enough to fit the end of the wire. Unscrew the cap.
Insert one end of the wire into the drilled hole and then caulk it into position. Use caulk that is rated for use with fuel (so it doesn't get compromised by the fuel). Let the caulk dry.
Screw the cap back onto the tube so the wire sticks up from the center by approximately 1 inch. Caulk the edges of the cap and tube.
