Hi-Flow Accelerator Pump Nozzle Screw

The Hi-Flow Accelerator Pump Nozzle Screw from Advanced Engine Design is a precision fuel system component engineered for carbureted and modern fuel-injected engines requiring optimized cold-start and acceleration enrichment. This small but critical fastener controls the flow rate and atomization of fuel delivered during throttle transition events, ensuring responsive throttle feel and smooth power delivery across the RPM band. Mechanics and engine builders rely on this component when tuning carburetor or fuel injection systems for improved drivability and fuel economy consistency.

Constructed to Advanced Engine Design's exacting tolerances, the Hi-Flow Accelerator Pump Nozzle Screw features precision metering geometry that regulates the volume of enrichment fuel injected during rapid throttle opening. The screw's internal orifice diameter and seat design work in concert with the pump discharge circuit to deliver the exact fuel pulse needed for seamless acceleration without hesitation or fuel stumble. At just 0.03 lbs with compact dimensions of 3.85 x 0.5 x 4.4 inches, it installs cleanly into standard carburetor mounting bosses and integrates seamlessly with both single-stage and dual-stage pump systems used in classic street machines and performance builds.

Carburetor enthusiasts, restoration specialists, and tuners working on muscle cars, hot rods, and vintage imports will find this nozzle screw essential for dialing in the pump circuit during baseline carburetor tuning. Proper accelerator pump calibration directly influences cold-start behavior, cruise quality, and wide-open-throttle response—factors that separate a mediocre tune from a refined one. Installation requires standard carburetor disassembly procedures; replacement of this component is recommended whenever servicing the fuel bowl or pump system to restore factory enrichment curves and eliminate flat spots during throttle transition.