1. Make sure the vehicle is on level ground.
2. Seat idle adjusting needles lightly and back them off exactly one full turn if there is any doubt about this having been done during reassembly. See Step 3 of "Reassembly -Throttle Body -Passenger Car Carburetors"
Do not seat the idle adjusting needles too tightly as this will grove the tips of the needles and prevent a smooth idle. If the needles become grooved, they must be discarded and replaced with new ones.
3. Start the engine and allow the operating temperature to reach normal. Reset the idle speed screw if necessary to obtain an idle rpm fast enough to prevent stalling during the warm-up period.
4. With the choke plates wide open and the
fast idle cam on passenger car carburetors in the
position where the idle speed screw contacts the
lowest step of the cam, adjust the idle to the specifide RPM with the idle speed screw.
5. 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 adjusting 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 halfway between these two points will result in a satisfactory idle mixture setting. Repeat this procedure with the other needle. If this adjustment results in an increased idle rpm, reset the idle speed screw to obtain the specified idle rpm, and again adjust both idle adjusting needles.
