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OVERHAUL

Carburetor rebuilding kits usually include specific procedures and exploded views for order of assembly and disassembly, therefore, only general applicable rebuilding suggestions are provided here. Efficient carburetion depends greatly on careful cleaning and inspection during overhaul since dirt, gum, water, or varnish in or on the carburetor parts are often responsible for poor performance.

Overhaul your carburetor in a clean, dust-free area. Carefully disassemble the carburetor, referring often to the exploded views. Be sure to keep all similar/look-alike parts segregated during disassembly and cleaning to avoid accidental interchange during assembly. Make a note of all jet sizes.

When the carburetor is disassembled, wash all parts (except diaphragms, electric choke units, pump plunger, and any other plastic, leather, fiber, or rubber parts) in clean carburetor solvent. Do not leave parts in the solvent any longer than is necessary to sufficiently loosen the deposits. Excessive cleaning may remove the special finish from the float bowl and choke valve bodies, leaving these parts unfit for service. Rinse all parts in clean solvent and blow them dry with compressed air or allow them to air dry. Wipe clean all cork, plastic, leather, and fiber parts with a clean, lint-free cloth.

Blow out all passages and jets with compressed air; be sure that there are not restrictions or blockages. Never use wire or similar tools to clean jets and valves. Also, be sure to clean all jets and valves separately to avoid accidental interchange.

Check all parts for wear or damage; replace all defective parts. During inspection, pay careful attention to the following:

  1. Check the float needle and seat for wear. If wear is found, replace the complete assembly.
  2. Check the float hinge pin for wear and check the float(s) for dents or distortion. Replace the float if fuel has leaked into it.
  3. Check the throttle and choke shaft bores for wear or an out-of-round condition. Damage or wear to the throttle arm, shaft, or shaft bore will often require replacement of the throttle body. These parts require a close tolerance of fit; wear may allow air leakage, which could affect starting and idling.

    NOTE: Throttle shafts and bushings are not usually included in overhaul kits, but they can often be purchased separately.

  4. Inspect the idle mixture adjusting needles for burrs or grooves. Any such condition requires replacement of the needle, since you will not be able to obtain a satisfactory idle.
  5. Test the accelerator pump check valves. They should pass air one way but not the other. Test for proper seating by blowing and sucking on the valve. Replace the valve if necessary. If the valve is satisfactory, wash the valve again to remove breath moisture.
  6. Check the bowl cover for warped surfaces with a straightedge.
  7. Closely inspect the valves and seats for wear and damage, replacing as necessary.
  8. After the carburetor is assembled, check the choke valve for freedom of operation.

    Carburetor overhaul kits are recommended for each overhaul. These kits contain all gaskets and new parts to replace those that deteriorate most rapidly. Failure to replace all parts supplied with the kit (especially gaskets) can result in poor performance later.

    Some carburetor manufacturers supply overhaul kits of three basic types: minor repair; major repair; and gasket kits. Basically, they contain the following:

    Minor Repair Kits:

    Major Repair Kits:

    Gasket Kits

    After cleaning and checking all components, reassemble the carburetor, using new parts and referring to the exploded view. When reassembling, make sure that all screws and jets are tight in their seats, but do not overtighten, as the tips could be distorted. Tighten all screws gradually, in rotation. Do not tighten needle valves into their seats; uneven jetting will result. Always use new gaskets. Be sure to adjust the float level when reassembling.

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