The accelerator pump covers the instant between opening the throttle and the main circuit catching up. When the diaphragm hardens or splits, you get a stumble off idle that no amount of jet changing will fix, because the shot of fuel simply is not being delivered. This is the 30cc gasoline diaphragm for 4150 style carburetors.

Edelbrock 12400 Accelerator Pump Diaphragm Details:

• 30cc pump volume, rubber construction.
• For gasoline use in 4150 style carburetors.
• Also listed for Holley, Barry Grant and Demon gasoline carburetors.
• Sold individually.
• Not for alcohol or E85 fuels, which require a different diaphragm material.

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

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