Edelbrock's AVS2 Off - Road Carburetor 1916 with Electric Choke is a special 650 CFM version of the proven 1906 street carb with Annular Flow Booster technology for near - EFI - like drivability that you can feel as soon as you step on the gas. Like AVS2 street carbs, the AVS2 Off - Road features an annular ring with eight evenly spaced orifices that replaces the standard single brass tube (down - leg) fuel feed. The AVS2 Off - Road booster ring distributes fuel into the airflow stream with an even spray that eliminates flat spots and greatly improves throttle response in the low - to mid - RPM range without sacrificing top - end power. For superior fuel control over rough terrain, the AVS2 Off - Road features a new spring - loaded needle and seat along with a spring - loaded anti - syphon ball in the accelerator pump circuit to prevent fuel drip common with standard carbs in off - road situations. The AVS2 Off - Road is unaffected by engine backfires since there are no power valves to blow out. For fast and simple part - throttle tuning, metering rods and springs can be changed in seconds without carburetor removal or fuel draining. AVS2 Off - Road carbs have the unique ability to hold a tune when compared to other carburetors. Your tuning and adjustments stay unchanged, so performance remains consistent. Updated primary and secondary booster clusters in the AVS2 Off - Road offer the most accurate and up - to - date calibration available for today's fuels and octane levels. Additionally, the unique Qwik - Tune Secondary Air Valve allows for limitless calibration of the secondary circuit. Adjustments can be with simple hand tools in seconds to suit your application. AVS2 Off - Road Carburetors feature a two - piece design for easy tuning that allows you to make float level adjustments or replace internal components without draining the carburetor or removing it from the engine. The AVS2 Off - Road 650 CFM is available with a manual (1915) or electric (1916) choke and are manufactured by Edelbrock in the USA