The Auxiliary (or Secondary) Venturi is designed to accelerate airflow through the carburetor throat. This helps pull fuel from the float bowl at low engine speeds, as well as contributing to off-idle throttle response. The 50 size is the largest available, recommended for large engines (500cc or more per cylinder, assuming one cylinder per throat). Fits Weber 45 DCOE only. Two required per carburetor; sold individually.
Note that this is the more common short version, designed to be used with a sleeve-retained air horn (not included).* It is held in place by a locking screw (Part No. WC-64840.003, not included). Fits both "Made in Italy" 45 DCOE, as well as current "Made in Spain" 45 DCOE models.
* Very old DCOE parts lists also show a longer version (Weber #69904) for use without air horns.
Note: Fits genuine Weber (made in Italy or made in Spain) carburetors only! Does not fit most copies, Asian knock-offs, or work-alikes.
