A soft copper washer between the inverted flare adapter and the carburetor housing like a brake line banjo fitting uses will solve the problem permanently. Just carefully draw file the carburetor housing to give the gasket a smooth surface to seal against. No it's not "original"- - - -yes, it works! Problem solved!
Jerry
I just wonder that if a male pipe fitting that goes all the way in can get tight enough for a washer to "crush seal" 4-6 PSI. Worth a try. Darren indicates he feels that it is tight.
