Owners manual

MANUAL CHOKE:

1. Connect the choke control cable (Holley® P/N 45-228) to the choke actuation lever, and lock in place with the choke cable

lock screw (Figure 8).

2. Mount the outer sleeve to the cable clamp.

3. Actuate the choke cable through its full range of motion to ensure full choke operation. Adjust, as necessary

Figure 8

IDLE MIXTURE NEEDLES:

Idle mixture needles control the air/fuel mixture at idle. These have been preset at the factory and SHOULD NOT need any

adjustments. However, if you feel that adjustment is necessary, you can use the following procedure to do so. When tuning the

idle mixture, you’re actually tuning for the best manifold vacuum. Idle mixture needles are found on the primary and secondary

metering blocks. If you change one idle mixture needle, you should change the other idle mixture needle by the same amount.

Here are the proper steps for setting the idle mixture needles.

1. Attach the vacuum gauge to a manifold vacuum port on the throttle body.

2. The Ultra Double Pumper™ is a 4 corner idle carburetor which means there are 4 idle mixture screws. Two in the primary

metering block and two on the secondary metering block. Adjust each idle mixture screw (Figures 10 & 11) 1/8 turn at a

time, alternating between all 4 screws. Turn them equally, until you achieve the highest possible vacuum reading without

adjusting the curb idle speed screw. Turn screws in to lean the mixture. Turn them out to richen the mixture.

Figure 9