> However, with a venting valve at least I could get > some liquid in the tank and then use the technique > of cracking the valve and listening for liquid.
Richard, I'd suggest a trip to your local radio control hobby shop - the big one that sells everything from helicopters to racing dune buggies. The small diesel engines have a variety of parts for fuel and water systems. [I found this, courtesy of Royce Brademan, when I was trying to seal the water bath around the fuel tank on my Accucraft C-16.] Or do a web search for "r/c fuel parts". I'll bet they have a small vent with a tap/valve on it that you could install. Pete
