HENKYO Accelerator Pump Discharge Nozzle Set for Holley‑style 4150/4160/4500 Carburetors — 4‑piece brass .031/.033/.035/.037 with

If you tune or restore classic performance carburetors, correctly sized accelerator pump discharge nozzles are essential for crisp throttle response and proper fuel atomization. This HENKYO kit gives you a selection of four straight brass jets machined to close tolerances so you can match the nozzle orifice to engine needs or drivability preferences. Each order includes one of each diameter: 0.031", 0.033", 0.035", and 0.037", plus copper gaskets designed to form a secure seal when installed.

How does choosing the right nozzle diameter affect throttle response?

Nozzle size changes how much fuel is shot into the carburetor throat during accelerator pump action. Smaller orifices deliver less volume and a sharper, leaner squirt; larger orifices increase volume for richer bursts. Picking the correct size helps reduce hesitation, stumbling, or excessive richness when you open the throttle quickly.

• 0.031" – leaner, for mild cam or low-load tuning
• 0.033" – slight increase for balanced response
• 0.035" – mid-range volume for moderate performance setups
• 0.037" – richest option for big cams or high-load needs

What materials and manufacture quality should I expect from this kit?

The set uses brass nozzles that resist corrosion and conduct heat steadily, helping consistent fuel flow in varied operating conditions. Each jet is produced on a high-precision CNC lathe to hold tight tolerances, and the included copper gaskets form a reliable seal to prevent leaks and maintain pump effectiveness.

• Brass construction for durability and corrosion resistance
• CNC-machined for accurate orifice dimensions
• Copper gasket included to ensure a leak-free seating

Which carburetors and applications are compatible with this nozzle set?

These straight accelerator pump jets are designed for common square-bore performance carbs—specifically models in the 4150, 4160, and 4500 families, plus many Holley-pattern 2300 variants. They work for rebuilds, jetting experiments, or swapping to tune transient fueling when modifying cam, intake, or exhaust components.

• Fits 4150/4160/4500-style carburetors and compatible 2300 variants
• Useful for carb rebuilds, dyno jetting, and street tuning
• Sold as a 4-piece set covering common pump sizes

How easy is it to install and test different nozzle sizes?

Installation is straightforward: remove the accelerator pump cover or bowl, swap the nozzle and gasket, then reassemble. Testing involves assessing throttle response and adjusting until the vehicle no longer hesitates or bogs on sudden throttle application. Keep a log of which size produces the best result for each engine setup.

• Simple swap—no special tools beyond basic carburetor tools
• Test by quick-throttle pulls at idle and part-throttle transitions
• Record results so you can revert or refine jetting choices

Who is this for: The HENKYO Ho-*lley accelerator pump discharge nozzle kit is aimed at mechanics, restorers, and performance hobbyists working on Holley-pattern carburetors. If you rebuild carbs, experiment with jetting, or need replacement pump nozzles for 4150/4160/4500-style units, this brass four-pack offers a practical range of sizes to fine-tune transient fuel delivery without sourcing individual jets.