Adjusting Engine Idle

Special Tools

1, Bring engine to operating temperature.

2. Check idle speed, If idle speed is too high or low, readjust air correction screws on throttle valve housings as needed. Turning screws in, lowers idle, Turning out, increases idle. Check air flow of individual cylinders at 1600-2000 rpm synchrometer, special tool P 235, See page SF 40 for adjusting instructions.


If resetting the air correction screws shows no reaction on the synchrometer. then the idle passages in the throttle valve housings are carboned up and must be cleaned.

3, Connect emission tester and check CO emissions. If CO value is not within the prescribed limit, shut off engine and readjust idle speed injection quantity on pump.


Do not start engine while adjusting idle speed injection quantity,

4, The idle adjusting screw can be reached with special tool P 230 c through a hole which is covered by a plastic cap in the cooling air upper shroud.

5. Remove cap.

CO emissions

6. Depress the spring-loaded idle adjusting screw with special tool P 230 c until you can feel it engage with the slot of the centrifugal governor.

USA Europa Carrera 2.7

lean lean

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Idle speed can change after CO emissions have been adjusted at idle speed (900 t 50 rpm).

7. Turn adjusting screw counter-clockwise for a leaner mixture and clockwise for a richer mixture.

Do not adjust by more than 1 notch at a time. A maximum of three notches is allowed to either the right or left of the basic adjustment.

9. Adjust idle speed by turning the air correction screws. Recheck with synchrometer.


Adjustments at idle speed and under partial load should be made as quick as possible so that the velocity stack area does not heat up. Drive the car a short distance or run engine slightly faster (about 3000 rpm) before making another CO test on road or dynamometer. This will cool off the velocity stack area.

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