Edelbrock Carburetor Troubleshooting

Our Edelbrock kit includes filter screens for each of the needle & seat assemblies.

Edelbrock Carburetor

Our kit also includes a screen filter for the inlet. If you use the inlet filter, the screen for the seat cannot be used. Hopefully you have an in-line fuel filter anyhow.

Watch a video about adjusting the Edelbrock 4 barrel carburetor float.

Surging

At part throttle your vehicle is surging (rpm is going up & down like a yoyo)

Don't blame the carburetor right away. Especially if you had this problem before rebuilding, or replacing the carburetor.

Chance are it's the timing, or the vent to the gas tank. Make sure the vent is clear. In some cases there may be a check valve in the vent line.

Throttle bushings required for the primary shaft: 22-172

Edelbrock Carburetor – Frequently Asked Questions (FAQs)

1. What size Edelbrock carburetor do I need for my engine?

The correct carburetor size depends on your engine’s cubic inches (CI) and maximum RPM. Use this formula to estimate CFM needs:
(CI × RPM) ÷ 3456 = CFM
For most small-block V8 street applications, an Edelbrock 600 CFM carb (like the 1406) works well.

2. How do I identify which Edelbrock carburetor I have?

Check the stamped number on the passenger side of the mounting base (near the throttle linkage). Common model numbers are 1405, 1406, etc.

3. Why is my Edelbrock carburetor idling rough?

Common causes include:

Incorrect idle mixture adjustment
Vacuum leaks
Faulty ignition timing
Clogged idle circuits or passages
Misadjusted floats

4. How do I adjust the idle mixture screws?

With the engine at operating temperature:

Turn both idle mixture screws in until lightly seated.
Back them out 1.5 turns as a baseline.
Turn each screw slowly in or out to achieve the highest, smoothest idle.
Recheck idle speed afterward.

5. My Edelbrock surges at idle—what causes that?

Likely culprits include a lean idle mixture, vacuum leak, or overly aggressive ignition timing. Richening the idle slightly or checking for intake gasket leaks may help.

6. Why is fuel leaking from the Edelbrock carburetor?

This usually indicates:

A stuck or leaking float
Needle and seat wear
Excessive fuel pressure (above 6.5 psi)
Edelbrock carbs require 4.5–6.5 psi maximum.

7. What is the correct float level for an Edelbrock carburetor?

Float height: 7/16"
Float drop: 15/16"
Measured with the top plate inverted and no gasket in place. Use a gauge or caliper for accuracy.

8. Can I run an Edelbrock carburetor without an electric choke?

Yes, manual or no-choke versions are available (like the 1405), but cold starts will require manual throttle feathering until warm.

9. Do I need a fuel pressure regulator with an Edelbrock carburetor?

Only if your mechanical or electric pump exceeds 5.5 psi. Too much pressure will flood the carb.

10. What base gasket should I use?

Edelbrock 4-barrel carbs use a square bore base. Use a thick, heat-insulating gasket to reduce heat soak and prevent fuel percolation.

11. How often should I rebuild my Edelbrock carburetor?

Rebuild every 30,000–50,000 miles, or if you notice:

Hesitation
Poor fuel economy
Idle issues
Black smoke from exhaust

12. Is ethanol fuel safe for Edelbrock carburetors?

Edelbrock carbs handle up to 10% ethanol (E10). For E85 or higher, use ethanol-compatible parts and seals or switch to EFI.

EDELBROCK