[AZKen]

Understood, probably updraft. The main jet plugs have copper ring gaskets as said. Don't know why new ones would leak. If they both leak. That means the same mistake, like wrong gasket, plug too tight, plug too loose; as opposed to a bad plug or threads. You WILL, of course, have to remove the carb and examine the cause. I think I would find new rings, try to find out how tight is tight, and replace. Examine the sealing face of plugs and sealing face of carb hole for burrs, nicks or worse. Examine how crushed the rings are. The carb is pretty easy to remove with minimal effort and a little spilled gas. Maybe these rings have a specific orientation, I.E. right way/wrong way against carb face.