Abstract: Apparatus for adjustment of the main metering jet of a modular type high performance engine carburetor avoiding the problem of having to partially disassemble the carburetor in order to change the main metering jets. The invention includes a continuously adjustable elongated metering rod having a tapering point proximate the fuel orifice hole of an elongated cylindrical fuel metering jet, the rod adapted to pass horizontally through the carburetor float bowl module to the outside of the carburetor for external adjustment. The main metering jet is modified by a transverse located opening to pass fuel to the longitudinal fuel orifice hole with a second larger diameter concentric longitudinal hole adapted to receive and guide the metering rod pointed end into the fuel orifice hole.