Maverick and Comet Repair

Fuel System

OVERHAUL
Carter YF, YFA
DISASSEMBLY
During the disassembly operations, refer to the exploded view of components which accompanies this section. Separate the throttle connector rod retainer from the choke connector rod and remove the rod from the fast idle link. Remove the automatic choke connector rod and remove the rod from the fast idle link. Remove the automatic choke components, including housing retaining screws, housing assembly, housing gasket and baffle plate, trip lever and pin assembly and fast idle link. Remove the air horn retaining screws, the dashpot and bracket, and the air horn and air horn gasket from the carburetor main body. With the air horn assembly inverted, remove the float pin and the float and lever assembly. With the air horn assembly turned upright, catch the needle pin, spring, needle and seat. Remove the float needle seat and gasket. Remove the air cleaner bracket and the choke plate retaining screws. If necessary, the ends of the screws may be filed and new screws used during assembly. Remove the choke plate. With the fast idle cam spring disengaged from the cam spring lever on the choke piston lever and shaft assembly, rotate the choke shaft and piston assembly in the counterclockwise direction until the choke piston is withdrawn from the choke piston cylinder. Remove the choke assembly from the air horn and remove the piston pin, piston, fast idle cam and spring from the piston lever and shaft assembly. With the main body casting inverted, catch the accelerating pump check needle as it falls out. With the throttle shaft arm spring disconnected, loosen the throttle shaft arm screw and remove the arm and pump connector link.

Remove the retaining screws of the accelerating pump diaphragm housing and withdraw the diaphragm assembly, lifter link, metering rod and fuel bowl baffle plate as a unit. Separate the metering rod arm spring from the metering rod and remove the metering rod from the assembly. Compress the upper pump spring and remove the retainer. Lift off the upper spring and remove the metering rod arm assembly and pump lifter link from the diaphragm shaft. Compress the lower spring and remove the spring retainer, spring and pump diaphragm assembly from the housing. Use a special tool or a screwdriver of appropriate size to remove the low speed jet and metering rod jet. Remove the retaining screws which attach the throttle body flange to the main body casting and separate the components. Remove the gasket between the throttle body and main body. Filing the ends if necessary, remove the screws which retain the throttle plate (use new screws during assembly) and slide the throttle shaft and lever assembly out of the throttle body flange.

NOTE: Do not remove the idle mixture limiter caps or the mixture screws from the throttle body.

ASSEMBLY
Prior to assembly, clean and inspect all components. Wash all components (except the accelerating pump diaphragm and the anti-stall dashpot assembly) in a suitable commercial solvent. Rinse all solvent-cleaned parts in kerosene to remove traces of the cleaning solvent, then dry with compressed air. Do not use wire or drills to clean openings in the carburetor—use of such devices will enlarge the hole or passage being cleaned, thus changing the operating characteristics of the carburetor.

Install the throttle shaft and lever assembly to the throttle body flange, then position the throttle plate on its shaft so that the notch in the plate is lined up with the slotted idle port in the throttle body flange. Install the throttle plate retaining screws so that they are snug, but not tight. Move and rotate the shaft to ensure that the throttle plate does not bind in its bore and reposition the plate if necessary. Tighten the throttle plate retaining screws and stake or peen into place.

Using a new gasket, join the main body casting with the throttle body flange and evenly tighten the retaining screws. Using the proper size screwdriver or special jet tool, install the metering rod jet and low speed jet. Install the pump diaphragm housing and position the lower spring on the diaphragm shaft and housing. Install the spring retainer, pump lifter link, metering rod arm and spring assembly, and the upper spring on the diaphragm shaft. Depress the spring and install the upper retainer. Install the metering rod to the meter rod arm as shown in the illustration accompanying the preceding section. Line up the pump diaphragm with its housing and install the retaining screws. Position the fuel bowl baffle plate on the pump assembly and line up the pump housing, pump lifter link, metering rod and baffle plate with the main body casting.

NOTE: Be sure that the vacuum passage in the diaphragm housing is lined up with that of the main body.

Install the assembly to the main body casting, being sure that the pump lifter link is engaged with the main body, that the baffle plate has its grooves in the main body, and that the metering rod is inserted into the metering rod jet. Install the pump housing screws so that they are snug, but not tight. Pushing down on the diaphragm shaft to compress the diaphragm, tighten the retaining screws evenly. Adjust the metering rod. Install the throttle shaft arm and pump connector link to the throttle shaft and pump lifter link. Tighten the locking screw and connect the throttle shaft arm return spring. Install the fast idle cam and spring to the choke lever and shaft assembly. Install the choke piston and pin to the choke piston lever and shaft, then disengage the cam spring from the lever and install the choke shaft assembly to the air horn. Align the piston with the cylinder, rotate the shaft assembly in the clockwise direction until the piston pin is inside the cylinder. Position the cam spring on the cam spring lever of the choke lever assembly.

NOTE: When the cam spring is properly positioned, the tangs on the cam and the choke lever will be lined up with one in front of the other.

With the choke plate in position on the shaft, install the retaining screws without tightening fully. As with the throttle plate, move and rotate the shaft to ensure that the plate moves freely, then tighten the screws and peen or stake to secure.

Install the needle valve seat and gasket in the air horn. Invert the air horn and install the needle, pin spring, needle pin, float and lever, and float pin. Adjust the float level. Install the pump check needle to the main body casting and position the air horn (with new gasket) and the anti-stall dashpot and bracket on the main body. Secure the dashpot bracket and evenly tighten the screws attaching the air horn to the main body. Install the choke trip lever and fast idle link to the choke housing. Be sure that the lever and link properly engage each other and the choke piston lever and shaft. Install the coil housing, gasket and baffle plate (with identification mark facing outward). The gasket should be between the baffle and the coil housing, and the thermostatic spring should engage the tang of the choke lever. Install the retainers and screws, set the housing to the proper setting, and tighten the screws. Install the air cleaner bracket and attach the throttle connector rod retainer to the fast idle link. Install the choke connector rod to the throttle lever and fast idle link. Secure the air horn to the main body and connect the connector rod retainer to the choke connector rod.

Carter RBS
DISASSEMBLY
Remove the anti-stall dashpot or solenoid and its bracket. Remove the choke housing retaining screws, the choke housing and its gasket and withdraw the choke piston lever, piston and wire link. (See accompanying illustration for choke housing components.) Remove the air cleaner anchor screw bracket. Remove the choke plate shaft fork lever, choke plate screws and plate, and withdraw the shaft from the carburetor body. Remove the fast idle cam retainer (with a screwdriver) and plastic collar. Remove the fast idle cam and separate the fast idle connector rod from the cam and fork lever of the choke plate shaft. Remove the connector link clip of the accelerating pump arm and free the pump arm retaining spring from the arm at the pump plunger end. Remove the retaining screw and retainer and withdraw the accelerating pump arm, spring and sleeve. Remove the fuel bowl and gasket and the inlet needle valve assembly.

Tap lightly on the upper end of the plunger shaft to remove the accelerating pump assembly. The pump cover, plunger and spring will drop from the lower end of the casting. Pry the conical washer from the diaphragm cover with a screwdriver and remove the metering rod and diaphragm assembly. The cover may be removed by piercing with a sharp tool and prying from the casting. If it is desired to remove the throttle plate or shaft, the throttle plate and the bottom of the mounting flange should be lightly marked to facilitate installation of the plate to its original position. Remove the throttle plate screws, being careful to avoid damage to the shaft, bore and shaft threads if the screws must be filed slightly. Remove the throttle plate and slide the throttle shaft and lever from the carburetor body. Remove the idle mixture limiter cap, idle mixture screw and spring and the idle speed screw and spring. Do not try to remove the slotted idle passage plug located below the idle mixture limiter. The plug is a press fit and should not be repositioned. Clean and inspect the components. noting that the diaphragm, anti-stall dashpot and solenoid should not be washed or soaked in the cleaning solvent and that wire or other hard objects should never be used to clean carburetor passages. Clean the solvent from the parts with compressed air.

ASSEMBLY
With the main body casting inverted, position the accelerating pump plunger, spring, spring seat and shims in the pump housing. Using a new cover assembly, press the pump cover components into the end of the housing. A 5/8 in. socket may be used to press the outer edge of the cover while it is lightly tapped into place on the main body casting. Force should not be exerted on the center of the pump cover. Install the idle jet in the main body and turn the carburetor to an upright position. Insert the metering rod halfway into the casting sleeve and drop it into the main body. Position the diaphragm spring and retainer over the diaphragm and install a new diaphragm cover. A 1/2 in. socket may be used to press on the diaphragm cover while it is being tapped in place. Using a 7/16 in. socket, as shown, install a new conical washer over the diaphragm cover and tap until the washer is flat in the main body. Noting the scribe marks on the throttle plate and main body, install the throttle shaft and lever and the throttle plate. The screws retaining the throttle plate on its shaft should be snug, but not tight. Close the throttle plate, turn the main body upside down and check to ensure that little or no light shows between the plate and bore when the body is held up to the light. Tap the plate lightly in order to ensure that it is seated. Hold the plate closed and tighten and stake the retaining screws. When securing the screws, use a block of wood to support the shaft and plate in order :o avoid damage to or bending of the plate or shaft.)

Assemble the accelerating pump connector link to the throttle link and install the retaining clip. Engage the accelerating pump arm with the pump plunger and position the pump arm return spring over the plastic sleeve. Position the lower tang of the spring into the groove in the main body, then install the pump arm retainer and the carburetor identification tag. Hook the upper end of the spring under the arm near the plunger. Install the choke shaft and choke plate. The hole in the choke plate should be on the lower edge and the plate retaining screws should not be tightened fully until the plate has been centered by tapping it lightly. Assemble the fast idle connector rod to the fork lever and crimp the forked ends of the lever to secure it to the choke shaft. Assemble the lower end of the fast idle connector rod to the slot in the fast idle cam and install the cam along with its plastic collar and retainer. Install the choke piston link to the choke piston lever and slide the piston into the vacuum cylinder in the choke housing, then attach the choke link to the choke lever. With the lever positioned on the end of the choke shaft, secure with the retaining screw. Ensure that the choke linkage has freedom of movement and that it does not bind in any position. Install the choke housing gasket and housing. Install the idle speed and mixture adjusting screws and their springs. The idle mixture adjustment limiter should be installed only after the air-fuel ratio has been adjusted with the engine at normal operating temperature. With the body inverted, install the needle valve components and the float assembly. Check the float level and adjust if necessary. Using a new gasket, install the fuel bowl. Replace the anti-stall dashpot or solenoid and bracket to the carburetor.