Been wanting to add some kinda extension to keep the stand-off fuel from escaping... so I spent some time at the local true value looking for that random part that would fit the bill. A 3/8" pipe coupler fit perfect after some minor boring out with a Dremel. Used a short 3/8" screw and a vice to press into the tube to create a flared opening. Worked great today - kept the fuel off my plane and ran smoothly after some work to the high speed needle.
Got about 1/8" clearance from the prop which is penty since the blades will only bend forward when throttling up.
somegeek