Curb Idle Speed Adjustment

Holley 6280 Carburetor Assembly:

HOLLEY 6280 2 Bbl
NOTE: Refer to Specifications for curb and fast idle speeds.

1. Verify ignition timing is properly set, if timing is correct move to step 2, if not go to Ignition Timing Adjustments.
2. Disconnect and plug vacuum hose at EGR valve.
3. Disconnect and plug hose from carburetor at the heater air temperature sensor.
4. Remove air cleaner assembly, then disconnect and plug canister purge hose at canister.
5. Remove PCV valve from valve cover and allow valve to draw underhood air.
6. Disconnect and plug vacuum advance at the Electronic Spark Advance (ESA) unit.
7. Connect a suitable tachometer to the engine.
8. Disconnect carburetor electrical connector from the engine wiring harness, then remove the green duty cycle wire and blue idle solenoid wire from the connector. Reconnect the connector less the two wires.

Grounding Carburetor Switch:

9. Ground the carburetor switch using a suitable jumper wire.
10. Attach suitable jumper wire between solenoid idle stop terminal (blue wire) and battery positive terminal. Use caution in jumping proper wire on solenoid. If battery voltage is applied to incorrect wire, damage to wiring harness could occur.
11. Start engine and allow to reach normal operating temperature, then open the throttle slightly to allow solenoid plunger to extend.
12. Remove solenoid outer spring and screw, then insert a 1/8" allen wrench into the solenoid and adjust idle speed to 775 RPM.
13. Install screw and spring until outer screw lightly bottoms out.
14. Remove jumper wire, then turn out solenoid screw until specified curb idle RPM is obtained.
15. Remove tachometer, connect vacuum hoses and install PCV valve and air cleaner assembly.
16. Disconnect carburetor electrical connector, then install green and blue wires in their correct positions. Reconnect carburetor electrical connector.