Accelerator Pump Dia 32/36 E38

OVERVIEW

If your air-cooled engine experiences a frustrating stumble or a "flat spot" the moment you tip into the throttle, it is highly likely that your accelerator pump diaphragm has reached the end of its service life. The EMPI Accelerator Pump Diaphragm for the 32/36 Progressive carburetor is a critical component designed to deliver an instantaneous shot of raw fuel into the venturi during transition. Without this precise mechanical injection, the engine leans out momentarily before the main circuit can take over, leading to hesitation that ruins the driving experience. This high-quality replacement from EMPI is engineered to restore that crisp, off-the-line performance that makes the 32/36 progressive carburetor one of the most popular upgrades for Volkswagen owners seeking a balance between fuel economy and power.

Modern pump gas is significantly more aggressive than the fuels of yesteryear, often containing ethanol blends that can cause older rubber compounds to swell, crack, or lose their flexibility. This EMPI diaphragm (Part #43-5727-0) is manufactured using advanced, fuel-resistant elastomers specifically designed to withstand the corrosive nature of today''s chemical additives. Whether you are running a genuine Weber DGV series or an EMPI EPC 32/36 version, maintaining a fresh diaphragm is essential for both performance and safety. A leaking diaphragm doesn''t just cause poor engine response; it can allow fuel to seep onto your hot intake manifold, creating a significant fire hazard. At Appletree Auto, we recommend inspecting this component annually to ensure your VW remains reliable and responsive on every journey.

FITMENT

This accelerator pump diaphragm is designed specifically for the 32/36 Progressive series carburetors commonly used in air-cooled VW performance conversions. Detailed fitment includes:

• Carburetor Models: Weber 32/36 DGV, DGAV, and DGEV Series.
• Carburetor Models: EMPI EPC 32/36 Progressive Carburetors.
• Volkswagen Beetle: All years equipped with a 32/36 Progressive carb conversion kit.
• Volkswagen Super Beetle: 1971-1979 models with progressive carb upgrades.
• Volkswagen Karmann Ghia: All years running the 32/36 setup.
• Volkswagen Bus / Type 2: 1600cc to 2000cc engines utilizing a single progressive carb manifold.
• Volkswagen Thing / Type 181: All models with 32/36 progressive induction.

SPECS

The following technical specifications ensure a perfect seal and proper mechanical displacement within your carburetor housing:

• Brand: EMPI
• Part Number: 43-5727-0
• Material: High-grade nitrile-reinforced elastomer for superior ethanol resistance.
• Mounting Pattern: Standard 4-hole square configuration for 32/36 housings.
• Center Plate: Integrated corrosion-resistant metal backing plate.
• Return Spring Compatibility: Works with standard internal pump return springs.
• Application: Accelerator pump circuit for primary/secondary progressive stage transition.
• GTIN: 707924416251

PRO TIPS

1. The Visual "Squirt" Test for Diagnostic Accuracy

Before you tear the carburetor apart, you can easily verify if your diaphragm is failing. With the engine off and the air cleaner removed, look down into the primary throat of the carburetor while manually pulling the throttle linkage. You should see a strong, steady stream of fuel shooting directly into the bore immediately as the linkage moves. If the stream is weak, delayed, or non-existent, the diaphragm is likely torn or the internal check valve is clogged. Always perform this test with a cold engine to minimize the risk of fire from stray fuel vapors.

2. Proper Alignment During Installation

When installing your new EMPI diaphragm, it is vital to ensure the internal return spring is seated perfectly in the center of the diaphragm''s metal plate. If the spring slips to one side during assembly, it can pinch the rubber or prevent the pump from making a full stroke. We recommend holding the carburetor at an angle so gravity helps keep the spring centered while you start the four cover screws. Tighten the screws in a "criss-cross" patternjust like lug nuts on a wheelto ensure even pressure across the sealing surface, which prevents vacuum leaks and fuel seepage.

3. Tuning the Pump Stroke for Maximum Performance

Replacing the diaphragm is the perfect time to fine-tune your "pump shot." On most 32/36 carburetors, there is an adjustment nut on the pump linkage rod. If you still experience a slight hesitation even with a brand-new EMPI diaphragm, you may need to increase the stroke length to provide a larger volume of fuel. Conversely, if the car puffs black smoke or "bogs" when you hit the gas, you might be getting too much fuel. Small adjustments of one or two turns can make a massive difference in how smoothly your VW transitions from idle to the main circuit.