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b. This adjustment should be very slight as the screw should have contacted the tab of the throttle shaft lever when it was first installed.   Turning the throttle stop screw out will slow the engine rpm down while turning it in will speed the rpm up.

2. Adjusting the Idle


b. Seat the idle adjusting needles lightly with the fingers and back them. off exactly one full turn if there is any doubt about this not having been done during reassembly.

Do not seal the idle adjusting needles too tightly as this will groove the tips of the needles and prevent a smooth idle. If the needles become grooved they must be discarded and replaced with new needles.

a. Make sure the vehicle is on level

a. Make sure the vehicle is on level


until it no longer contacts dashpot stem. It is important that the adjusting screw does not interfere with the normal idle setting of the carburetor. If the adjusting screw prevents the throttle lever from reaching the idle position, an excessive idle speed will result. The dashpot adjustment will be performed after the idle adjustments have been completed.


Figure 40. Dashpot Adjustment

c. Start the engine and allow the operating temperature to reach normal. If stalling prevents setting the idle adjusting needles, reset the throttle stop screw.

d. Set the idle adjusting needles to give the highest steady manifold vacuum reading, or the smoothest running and maximum idle speed if no vacuum gauge is available. This can be accomplished by turning one idle needle in until the engine begins to slow down, then backing the needle off over the "high spot" until it again begins to slow down. Setting the idle adjusting needle half way between these two points will provide a satisfactory idle. However, best performance will be obtained if the idle mixture is slightly on the rich side. Adjust first one needle and then the other. After the idle mixture has been properly adjusted it may be necessary to reset the throttle stop screw to the specified rpm.

c. Set the dashpot adjusting screw to obtain the specified clearance between the dashpot adjusting screw and dashpot. This setting should be made with the dashpot stem in the fully compressed position. Consult the current Holley Catalog Sheets for correct clearance.


Figure 41. Carburetor Adjustments

3. Dashpot Adjustment (Vehicles with Automatic Transmission)

4. Accelerating Pump

a. Adjust only when engine has reached operating temperature, making sure the drive selector is set at "neutral".

a. The throttle lever is providedwith three pump link hole positions to vary the pump discharge according to seasonal requirements.

b. Turn in the dashpot adjusting screw

b.   The No. 1 hole (nearest the throttle


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