Edelbrock 1906 AVS2 Carburetor 650 CFM Instruction Manual

Product Overview

The Edelbrock AVS2 Series 1906 is a satin-finished four-barrel carburetor with electric choke, designed and calibrated for optimum street performance in engines requiring an air-fuel flow of 650 CFM. This AVS2 model serves as an ideal replacement or upgrade, featuring annular flow primary boosters and a new calibration for improved off-idle and cruising performance. The annular flow booster design enhances fuel atomization, effectively eliminating flat spots during the transition from idle to full throttle. Each annular flow booster incorporates eight equally spaced orifices, optimizing fuel metering from idle to the main circuit. This design makes the carburetor suitable for a wide range of small- and big-block engines, compatible with both dual- and single-plane intake manifolds. The Edelbrock AVS2 #1906 includes both timed and full vacuum ports for ignition advance. It comes with .101 primary and .098 secondary metering jets, .070 x .037 metering rods, and an orange (5" Hg) step-up spring. For installation, Carburetor Stud Kits #8008 or #8024 may be used. It is recommended to match this carburetor with Edelbrock Performer, Performer EPS, RPM Air-Gap, Performer RPM, Torker II, or other similarly designed intake manifolds.

⚠ WARNING: THIS PRODUCT CAN EXPOSE YOU TO CHEMICALS WHICH ARE KNOWN TO THE STATE OF CALIFORNIA TO CAUSE CANCER OR BIRTH DEFECTS OR OTHER REPRODUCTIVE HARM. FOR MORE INFORMATION, VISIT WWW.P65WARNINGS.CA.GOV.

Image: California Proposition 65 Warning Label, indicating potential exposure to harmful chemicals.

What's Included

• Edelbrock 1906 AVS2 Carburetor
• Fuel Filter
• Base Gasket
• Instruction Manual
• Air Cleaner Gasket
• Carb Gasket (for intake)
• Wires for Electric Choke
• Plug for Brake Booster (if not used)
• Threaded Rod for Air Cleaner
• Vacuum Tee
• Throttle Stud

Image: The Edelbrock 1906 AVS2 Carburetor shown with its instruction manual, gaskets, wiring for the electric choke, and various small components for installation.

Image: The Edelbrock 1906 AVS2 Carburetor and its accompanying parts, including a Spanish instruction manual, gaskets, and wiring.

Setup and Installation

General Overview

The Edelbrock AVS2 carburetor is designed for straightforward installation and operation. Out of the box, it should be ready for basic functionality. Fine-tuning is primarily for optimizing performance for your specific engine. Refer to the detailed instruction manual provided for precise setup procedures and specifications for all models.

Image: Front view of the Edelbrock 1906 AVS2 Carburetor, highlighting its satin finish and electric choke mechanism.

Image: Another front view of the Edelbrock AVS2 Carburetor, showing the main body and fuel inlet.

Image: Side view of the Edelbrock 1906 AVS2 Carburetor, clearly showing the electric choke assembly and various linkages.

Image: Top view of the Edelbrock 1906 AVS2 Carburetor, showing the air horn and primary/secondary barrels.

Image: Bottom view of the Edelbrock 1906 AVS2 Carburetor, revealing the throttle plates and mounting points.

Vacuum Connections

• **Vacuum Advance:** Connect your vacuum advance line from the distributor to either the full vacuum port (always active) or the timed vacuum port (active based on throttle position). The timed port is typically preferred for performance applications.
• **PCV Valve:** Connect the PCV (Positive Crankcase Ventilation) valve from the valve cover to the designated port on the carburetor.
• **Brake Booster:** The large port at the rear of the carburetor is for the brake booster. If not used, ensure it is properly plugged.

Idle Mixture Adjustment

The idle mixture screws (two on the front of the carburetor) control the fuel-air mixture at idle. These are adjusted in pairs (left and right). To adjust:

1. Set engine RPM to approximately 800 RPM using the idle speed screw (located on the throttle linkage).
2. Adjust the mixture screws incrementally, alternating between left and right, to achieve either the highest RPM or the highest vacuum reading (using a vacuum gauge connected to the manifold vacuum port).
3. If RPM increases significantly during adjustment, reset the idle speed screw back to 800 RPM and continue fine-tuning the mixture.

Fuel Line Connection

Connect the 3/8-inch rubber fuel hose to the fuel inlet on the carburetor, securing it with a hose clamp. Ensure the fuel line has adequate clearance from other components, especially if using a drop-base air cleaner. A "banjo fitting" (available from Edelbrock) can be used to provide flexible routing and clearance if needed.

Throttle Linkage

Attach the throttle cable to the throttle stud on the carburetor linkage. For vehicles with kick-down cables or TV cables (e.g., 700R4 transmissions), an appropriate bracket may be required to ensure correct geometry and prevent transmission damage. Edelbrock offers specific brackets for this purpose. It is highly recommended to use the correct bracket to avoid issues with transmission shifting and longevity.

Electric Choke Wiring

The electric choke requires a 12-volt power source. The ground connection can be made by attaching the ground wire to one of the mounting bolts on the electric choke housing. For power, connect the positive wire to an accessory port on your vehicle's fuse panel. Avoid connecting directly to the ignition coil or other non-switched power sources to prevent battery drain or improper choke operation.

Operating Instructions

Accelerator Pump Adjustment

The accelerator pump has three different positions to adjust the amount of fuel delivered when the throttle is first opened. The carburetor comes factory-installed in the middle position. Moving the linkage to the top position provides a richer mixture (more fuel), while moving it to the bottom position provides a leaner mixture (less fuel). Adjust this based on your engine's response and performance needs.

Step-Up Springs and Metering Rods

The step-up springs and metering rods, located beneath the vacuum-controlled covers, influence fuel delivery under varying vacuum conditions. These are factory-set according to the carburetor's specifications (e.g., orange 5" Hg spring for the 1906 model). While not typically adjusted immediately, tuning kits with different springs and rods are available for advanced users to fine-tune the fuel curve for specific engine modifications or driving conditions. A vacuum gauge is essential for accurate adjustment of these components.

Maintenance

Regular maintenance is crucial for the longevity and optimal performance of your Edelbrock AVS2 carburetor. This includes:

• Periodically inspect all fuel lines and connections for leaks or wear.
• Check and replace the fuel filter as recommended by your vehicle's manufacturer or if signs of clogging appear.
• Ensure all vacuum lines are securely connected and free from cracks or damage.
• Keep the carburetor exterior clean to prevent debris buildup.
• Consult the detailed instruction manual for specific cleaning procedures and recommended service intervals.

Troubleshooting

If you encounter issues with your carburetor, refer to the troubleshooting guide in the provided instruction manual. Common issues may include:

• **Rough Idle:** Check idle mixture screw settings, vacuum leaks, and ignition timing.
• **Stalling:** Verify fuel pressure, float level, and proper choke operation.
• **Hesitation/Flat Spots:** Adjust accelerator pump linkage or consider changing step-up springs/metering rods.
• **Fuel Leaks:** Inspect gaskets, fuel lines, and float levels.

For complex issues, professional assistance from a qualified automotive technician is recommended.

Specifications

Warranty & Support

For warranty information, technical support, or to purchase replacement parts, please visit the official Edelbrock website or contact their customer service department. Keep your purchase receipt and product model number (1906) handy for any inquiries.

Visit the Edelbrock Store on Amazon for more products and information.