Carburetor - Carter YFA 1-Bbl: Overhaul: Disassembly

NOTE: Use new gaskets and seals. Make sure that new gaskets fit correctly and that all holes and slots are punched through and correctly located.

Remove carburetor from engine. Remove thermostatic spring housing assembly, spring housing gasket, index plate, choke over center spring, if equipped and fast idle link. Remove EGR WOT dump valve and bracket. If equipped, remove front mounted solenoid and bracket.
On Feedback carburetor, remove pull-down diaphragm adjustment limiting shield. Remove 2 retaining screws; disconnect choke pull-down link and remove pull-down motor assembly. Disengage link from choke shaft lever.
Remove air horn assembly screws and dashpot. On YFA Feedback model, remove feedback solenoid and bracket assembly. Lift air horn away from main body and remove gasket. Turn air horn upside-down and remove float pin, float and lever assembly.
Turn air horn right-side-up and catch needle pin, spring and needle as they fall out. Remove needle seat and gasket.
Remove air cleaner bracket. If necessary, file staked (burred) ends of choke plate attaching screws and remove. Be sure to use new screws when assembling. Remove choke plate from air horn. Remove choke link lever and attaching screw.
Turn choke shaft and piston assembly counterclockwise until choke piston comes out of choke piston cylinder. Remove assembly from air horn. Remove piston pin and piston from choke piston lever and shaft assembly.
Remove spring retainer from mechanical fuel bowl vent flapper valve. Remove vent shaft rod and spring and flapper valve. Note position of spring on rod for reassembly.
Turn main body upside-down and catch accelerator pump check ball and weight. Remove bowl vent lever screw in end of throttle shaft. Remove spring washer, actuating lever, operating lever and clip.
Loosen throttle shaft arm screw. Remove arm and accelerator pump connector link. Remove fast idle cam and screw. Remove throttle kicker, if equipped.
Remove accelerator pump diaphragm housing screws. Lift out pump diaphragm assembly, pump lifter link and metering rod as a unit. Remove lifter link seal.
Disengage metering rod arm spring from metering rod. Remove metering rod from rod arm assembly. For reassembly, be sure to note location of any washers that were used for shimming either spring. Compress upper pump spring and remove spring retainer.

Fig 1: Exploded View of Carter Model YFA 1-Barrel Feedback Carburetor (YFA Similar)
Remove upper spring, metering rod arm assembly, anti-rock plate, if equipped and pump lifter link from pump diaphragm shaft.
Compress pump diaphragm spring, remove pump diaphragm spring retainer, spring and pump diaphragm assembly from pump diaphragm housing.
Using proper size jet tool or screwdriver, remove metering rod jet and low speed jet. Remove screws and separate throttle body flange assembly from main body casting. Remove gasket.
Remove throttle plate retaining screws. File staked (burred) ends if necessary, and use new screws at reassembly. Slide throttle shaft and lever assembly out of throttle body.
NOTE: Location of torsion spring ends on throttle shaft is important to know for reassembly.
When removing idle mixture limiter cap, be sure to note the position of the tab.
Remove idle mixture screw adjustment limiting cap and cup as follows: Invert carburetor assembly and tape all vacuum and fuel connection openings.
Using a hacksaw, saw a slot lengthwise through thickness of cup. See Fig 2 . Be careful not to touch throttle body with saw blade. Insert screwdriver in new slot, spreading outer cup enough to remove inner cap.

Fig 2: Idle Mixture Screw Limiter Cap Removal Saw a slot through thickness of cup.
After removing limiter cap, count number of turns to lightly seat needle. This information should be used for reassembly. Remove mixture screw, spring and cup.