Description
Product Overview
The Pirate Mfg accelerator pump diaphragm is engineered for precision and durability. Constructed from an alcohol‑resistant polymer, it tolerates ethanol blends and EFuel without degradation. Compatible with Weber 40‑44‑48 IDF carburetors, the RS703‑DE model replaces the original diaphragm, restoring optimal fuel metering and throttle response. Weighing just 2.08 ounces, it offers a lightweight solution without compromising strength.
Usage
Designed for both street and track applications, this diaphragm performs reliably in everyday driving and high‑performance racing environments. It fits seamlessly into standard Weber IDF carburetors, making it suitable for daily commuters, weekend racers, and custom build enthusiasts who demand consistent fuel delivery across various fuel types, including high‑octane blends up to 110+. 
Why Choose Us
Pirate Mfg combines decades of carburetor expertise with modern material science. Our diaphragm undergoes rigorous testing for ethanol compatibility, ensuring long‑term reliability. Each unit is inspected for dimensional accuracy, guaranteeing a perfect fit that eliminates leaks and performance loss. Backed by a 5‑star customer rating, our product reflects a commitment to quality and rider confidence.
Key Features
- Ethanol‑resistant polymer for safe use with modern fuel blends
- EFuel certified, preventing degradation from alcohol content
- Fits Weber 40‑44‑48 IDF carburetors (RS703‑DE)
- Compatible with high‑octane racing fuels up to 110+
- Lightweight design (2.08 oz) for easy installation
FAQ
Is this diaphragm compatible with all Weber IDF models?
Yes, it is designed to fit Weber 40, 44, and 48 IDF carburetors, matching the original specifications.
Can I use this part with ethanol‑rich gasoline?
Absolutely. The diaphragm material is specifically formulated to resist ethanol and EFuel, ensuring reliable operation.
Do I need special tools to install the diaphragm?
No special tools are required. Standard carburetor service tools are sufficient for a straightforward replacement.
Will this work with high‑octane racing fuels?
Yes, the diaphragm is rated for use with fuels up to 110+ octane, making it ideal for performance applications.
What is the warranty on this product?
Pirate Mfg offers a one‑year limited warranty covering manufacturing defects.





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