Tip: Take plenty of digital pictures along the way in case you have a question about something later.
Choke PullOff Solenoid Remove the retaining clip, two screws and remove the solenoid from the bracket. (fig. 1)
Air Horn Remove fuel inlet filter plug and filter assembly (fig. 2)
Remove retainer clips and choke operating rod, then remove five air horn screws and remove the air horn (fig. 3)Remove float hinge pin, float and fuel inlet needle.
Remove fuel inlet seat and gasket. Remove power valve economizer (fig. 4B)
Remove evaporation control system diaphragm (fig. 5)
Don’t take the choke plates & shaft apart unless there is a good reason. You might break a screw causing more problems than it is worth.
Remove choke water housing screw, housing & gasket (fig. 6)
Remove 3 choke bimetal screws, ring thermostat housing & gasket.
Remove 3 screws from choke housing & remove housing & disengaging fast idle rod (fig. 7)
Remove ‘O’ ring from vacuum passage (fig. 8)
Remove choke housing shaft nut, lever, spring retainer & cam from choke housing shaft.
Remove screw & remove bushing spring washer, fast idle lever and washer from housing.
Remove 3 screws & remove diaphragm cover spring and diaphragm and shaft from housing.
Remove diaphragm adjusting screw from cover.
Accelerator Pump (fig. 9)
Remove 3 screws and remove pump cover, diaphragm and return spring from housing. Body (fig. 10)
Remove primary high speed bleed and main well tube.
Remove secondary high speed bleed and main well tube. Write down sizes of air bleed restrictions and main well tubes so that primary and secondary can be reinstalled in the proper channels.
Remove primary and secondary main metering jet, noting their size so they may be installed properly.
Remove power valve assembly.
Remove pump discharge nozzle and two pump discharge weight balls.
Hot Idle Compensator (fig. 11)
Remove cover plate and remove hot idle compensator and gasket.
Throttle Lever and Idle Stop Solenoid (fig. 12)
Remove 2 screws and remove idle stop solenoid and braket. Straighten lock washer and remove nut, lock washer, primary throttle lever, washer, secondary operating lever, spring and idle stop level
Cleaning and Inspection
Thoroughly clean all carburetor castings and metal parts. We use an ultrasonic cleaner, but when you don’t have that then the next best thing is to soak in Gunk Hydro Seal II HS. Follow up with hot tap water and Berryman’s B-12 ChemTool spray carburetor cleaner.
Any rubber parts that will be reused should not be soaked in any cleaner.
Blow out all passage ways with compressed air. I generally don’t like running wire in the passage ways because it can distort the size, the use of ethanol these days makes it necessary. Ethanol can leave white powder residue in the passage ways and if you don’t get it out, the carburetor will not run properly.
Inspect all parts for wear.
Always replace your float if you have the black Nitrophly float. These floats will absorb fuel over time and these floats are solid so shaking them won’t help. Replace the float, or you chance having problems that are hard to diagnose.
Inspect the throttle shaft for excessive wear. Over time the shaft can wear to the point that you develop a vacuum leak and you will have a rough idle. Always rebuild your carburetor using a new carburetor kit.
Ethanol has probably caused some damage to any rubber part that it has had contact with.
Stay away for old carburetor kits when possible. The gaskets and rubber parts may have become brittle if the kit sat on a shelf for any extended period of time.
Replace the fuel filter at this time.
Refer to disassembly illustrations and reverse disassembly procedure.
Once the float has been assembled to the air horn, adjust it.
Float Adjustment With the air horn in inverted position and float tang resting lightly on fuel inlet needle, insert specified gauge between air horn and top of float. These days this means measure the distance. Bend the tang if adjustment is required (fig. 14)
After assembly, adjust secondary throttle stop screw (fig. 15). Back off screw until secondary throttle plate seats in the bore. Turn screw in until it touches the tab on secondary throttle lever. Turnscrew an additional 1/4 turn.