METERING ROD

With throttle valve seated in bore of carburetor, press down on upper end of diaphragm shaft until diaphragm bottoms in vacuum chamber. Metering rod should contact bottom of metering rod well, and metering arm should contact lifter link at the outer end nearest the springs and at supporting lug. Adjust by bending lip of metering rod arm to which metering rod is attached, up or down as required.

1. Remove the carburetor air horn and gasket from the carburetor.
2. Back out the idle speed adjusting screw until the throttle plate is closed tight in the throttle bore.
3. Press down on the end of the pump diaphragm shaft until the assembly bottoms.
4. To adjust the metering rod, hold the diaphragm assembly then turn the rod adjustment screw until the metering rod just bottoms in the body casting.
5. Turn the metering rod adjustment screw in (clockwise) one additional turn for the final adjustment.
6. Install the carburetor air horn and a new gasket on the carburetor.

IDLE VENT ADJUSTMENT

This adjustment should be made after completing pump and metering rod adjustments. Install bowl cover and air horn assembly with gasket. With throttle valve tightly closed in carburetor bore, there should be the clearance listed in your spec chart between idle vent valve and inside of bowl cover. Adjust idle vent screw as required.

FAST IDLE ADJUSTMENT

Unit with built-in auto choke:

Remove choke coil housing, gasket, and baffle plate. Crack throttle valve (barely open) and hold choke valve firmly in closed position, then close throttle valve. This will allow the fast idle cam to revolve to the fast idle position.

With choke vlave held tightly closed, and with slight tension on throttle lever, there should be the clearance listed in your spec sheet between the throttle valve and carburetor bore (side opposite idle port). Adjust by bending connector link as required.

FAST IDLE CAM SETTING

1. Position the fast idle screw on the kickdown step of the fast idle cam against the shoulder of the high step.
2. Adjust by bending the choke plate connecting rod to obtain the specified clearance between lower edge of the choke plate and the carburetor bore.

CHOKE UNLOADER ADJUSTMENT

With throttle valve held wide open and choke valve held toward closed position with a rubber band, there should be the clearance as listed on your spec chart between lower edge of choke valve and inner air horn wall.

On carbs as shown in the image below, adjust by bending arm on choke trip lever.

On carbs shown in this image, adjust by bending unloader tang on throttle lever.

VACUUM BREAK ADJUSTMENT

With vacuum break arm held against its stop, and choke valve held toward closed position with a rubber band, bend vacuum break link to obtain the clearance listed in the spec chart between lower edge of choke valve and air horn wall.