Yep Jetmech they are called Idle Bar plugs, not all that many out there anymore. Egrave1 Its not real clear that you are using the engine inverted or just now mounted it that way.

Its imperative when using an inverted mount that the fuel tank is lowered in the fuselage to approximately the same tank height to carb spraybar relationship as when the engine is mounted upright. Failure to do this always can cause running problems as well as hydro lock and syphoning problems.

John