Fix It

Explore » home» a » adjust » carb » holley » how » idle » mixture » on » the » to » How to Adjust the Idle Mixture on a Holley Carb

---

How to Adjust the Idle Mixture on a Holley Carb

Adjusting the idle mixture of your Holley carburetor is an important procedure in the operation of the motor. The proper adjustment of the carburetor can improve your fuel mileage as well as keep the engine running more efficiently. Adjusting the two idle mixture screws of the Holley carburetor only takes a few minutes and requires only a couple of tools. Save the time and money it takes to visit a mechanic by adjusting the carburetor yourself.

Instructions

1

Locate the two idle mixture screws (one on each side) of the Holley carburetor and turn both screws carefully counterclockwise with a screwdriver until they bottom out and you feel resistance. Do not over-tighten the idle screws.

2

Turn both screws one-and-a-quarter turns clockwise with a screwdriver to find the idle adjustment starting point. Start the motor and allow it to warm up for about five minutes.

3

Remove the rubber vacuum hose from the metal vacuum port on the side of the carburetor and attach the vacuum gauge hose to the end of the port. Have someone place the car in gear and hold it still while you are adjusting the idle mixture screws.

4

Turn the idle screws one quarter-turn clockwise at a time in sequence with a screwdriver until you have the highest vacuum readings for both idle mixture screws. Put the car into park and leave it idling.

5

Repeat the procedure in Step 4, adjusting the idle mixture screws with a screwdriver while the vehicle is in park, until you get the highest vacuum readings. Remove the vacuum gauge from the carburetor vacuum port and reattach the vacuum hose to the port.