#### OVERHAUL

CAUTION
Never smoke when working around gasoline! Avoid all sources of sparks or ignition. Gasoline vapors are EXTREMELY volatile!

Efficient carburetion depends greatly on careful cleaning and inspection during overhaul, since dirt, gum, water and/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. Keep all similar and 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 the 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 to allow them to air dry. Wipe clean all cork, plastic, leather and fiber parts with a clean, lint-free cloth.

Fig. 1: Exploded view carburetor assembly — CA20 engine

Fig. 2: Exploded view carburetor assembly — CA20 engine

Fig. 3: Exploded view carburetor assembly — CA20 engine

Blow out all passages and jets with compressed air, be sure that there are no restrictions or blockages. Never use wire or similar tools for cleaning purposes; clean the jets and valves separately, to avoid accidental interchange.

Check all the parts for wear or damage. If wear or damage is found, replace the defective parts. Especially check 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 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 included in overhaul kits. They can 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/or 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:

   - All gaskets
   - Float needle valve
   - Volume control screw
   - All diaphragms
   - Spring for the pump diaphragm Major Repair Kits:
   - All jets and gaskets
   - All diaphragms
   - Float needle valve
   - Volume control screw
   - Pump ball valve
   - Main jet carrier
   - Float

   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 will 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.