1939-Up Carter BB Downdraft Carburetor Service Procedure

This is Carter Carburetor's "Circuit" service procedure for 1939 and later BB downdraft carburetors, issued as Form 3358B in April 1939 and revised in August 1948 by Carter Carburetor, a division of ACF Industries in St. Louis. It covers the carburetor itself rather than a particular car make.

Forty-eight numbered, photographed steps take the BB apart and put it back together. Disassembly covers the throttle lever, air horn, float and lever, idle orifice tube, step-up piston and jet, accelerating pump plunger and check balls, main metering jet, body flange and insulator, main vent tube (tool T109-195), needle seat, and choke valve and shaft. Parts are then cleaned and sorted into five circuit groups: float, idle, high speed, pump and choke. Reassembly notes include throttle valve orientation, the large discharge and small intake check balls, main vent tube installation with tools T109-70 or T109-151, float level setting, and the fast idle rod and cam. A closing note explains which flange gasket to use on cars with and without a governor. Mechanics and restorers rebuilding a BB carburetor will find it a compact checklist.

This 4-page copy is free to read online. Use the page box and thumbnails beside the reader to move between pages.