Volkswagen Front Wheel Drive 1974-1989 Repair Guide

Carburetor

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The 1974 Dasher uses a Solex 32/35 DIDTA two barrel carburetor with a vacuum operated secondary throttle. The 1975 Dasher uses a Zenith 2B3 two barrel carburetor. It, too, has a vacuum operated secondary throttle. The Rabbit and Scirocco carburetor is a Zenith 2B2 two barrel which also has a vacuum operated secondary throttle.

Some 1978 and 1980 Rabbits are equipped with a single barrel Solex 34 PICT-5 carburetor. Some 1982 and later carburetor equipped models use a Carter TYF feedback model.

ADJUSTMENTS



Solex 32/35 DIDTA Carburetor
THROTTLE GAP (BASIC SETTING)

See Figure 1

This adjustment is made at the adjuster screw located in the linkage on the carburetor, below and to the right of the automatic choke unit.

  1. Open the choke and close the throttle.
  2.  
  3. Turn the first stage adjusting screw out until there is a gap between it and its stop. The first stage throttle valve should be fully closed now.
  4.  
  5. Turn the adjusting screw in until it just touches its stop.
  6.  
  7. Turn the screw in 1 / 4 turn more and lock it.
  8.  
  9. The second stage throttle (secondary) should only be adjusted when it is definitely out of adjustment.
    1. Loosen the adjusting screw until the secondary throttle closes.
    2.  
    3. Turn the screw in 12 turns and lock it.
    4.  
    5. Adjust the idle mixture after this adjustment.
    6.  

  10.  



Click image to see an enlarged view

Fig. Fig. 1: Second stage adjusting screw (arrow)

FUEL LEVEL

This adjustment is made with the carburetor installed on the engine. Incorrect fuel level can cause stalling or high speed miss.

  1. Remove the air cleaner.
  2.  
  3. Remove the five carburetor cover mounting screws.
  4.  
  5. Plug the fuel inlet with a finger and lift off the carburetor cover and gasket. Set them to the side, leaving the linkages attached.
  6.  
  7. On models with the original equipment float (which is shaped like a child's top), with the float in the up or closed position, the distance from the edge of the float rim to the carburetor surface (minus the gasket) should be 0.59-0.63 in. (16-17mm).
  8.  
  9. Adjust the float by varying the thickness of the fiber sealing ring under the float needle valve.
  10.  
  11. On models with an aftermarket float (which is more rectangular in shape), with the float in the up or closed position, measure from the top edge of the float closest to the throttle chambers down to the carburetor surface (minus the gasket). The distance should be 1.46-1.54 in. (37-39mm).
  12.  
  13. Adjust the float by bending the tab that contacts the needle valve.
  14.  

For added accuracy, when measuring the float level, make all measurements with the carburetor top at a 45 degree angle so that the stop ball in the needle valve is not pushed down by the weight of the float.

FAST IDLE

See Figure 2

It will be necessary to remove the carburetor from the engine to perform this operation.

  1. Turn the carburetor upside down and drain the fuel from it.
  2.  
  3. With the carburetor upside down, close the choke tightly and measure the gap between the lower edge of the throttle valve and the housing wall with a drill. The measurement should be:

    All Except Calif. Manual Trans.-0.030-0.034 in. (0.80-0.85mm)
     
    Calif. Manual Trans.-0.024-0.028 in. (0.60-0.70mm)
     

  4.  
  5. Adjust the fast idle speed at the eyebolt fitted in the choke lever attachment.
  6.  



Click image to see an enlarged view

Fig. Fig. 2: Fast idle adjuster (arrow)

CHOKE VALVE GAP

See Figure 3

  1. Remove the automatic choke cover with the water hoses still attached.
  2.  
  3. Push the plunger rod down into its seat, then move the choke valve toward the fully closed position.
  4.  
  5. With an appropriate size drill bit, measure the gap between the choke valve and the carburetor housing. It should be 0.142-0.154 in. (3.5-4.0mm) on all except California models and 0.134-0.146 in. (3.5-3.7mm) on California models.
  6.  
  7. Adjust the choke gap by bending the lever arm attached to the plunger rod.
  8.  



Click image to see an enlarged view

Fig. Fig. 3: Adjust the choke gap by bending the lever (A)

When installing the choke spring inside the choke cover, the loop in the spring must go over the protruding choke lever. Insert the spring so that it uncoils in a clockwise direction (facing you).

AUTOMATIC CHOKE

Align the mark on the automatic choke cover with the mark on the carburetor by loosening the three retaining screws and turning the choke cover with the hoses still attached.

DASHPOT

See Figure 4

The purpose of the dashpot is to keep the throttle from snapping shut and stalling the engine. The dashpot has a plunger that extends when the throttle is closed suddenly. The plunger contacts a tab on the throttle lever and holds the throttle open slightly for a second, then closes the throttle slowly over the period of another second or so.

Not all models have dashpots.

  1. Close the throttle valve and make sure the choke is fully open. You may have to run the car up to operating temperature.
  2.  
  3. Press the dashpot plunger in as far as it will go.
  4.  
  5. Measure the gap between the plunger and its striking surface. It should be 0.04 in. (1mm).
  6.  



Click image to see an enlarged view

Fig. Fig. 4: Measure the gap between the plunger and its striking surface

  1. Adjust by loosening the lock nut and moving the dashpot on its threads.
  2.  

Zenith 2B3 Carburetor
THROTTLE GAP

See Figures 5 and 6

To adjust first stage throttle gap:

  1. The choke must be open and the first stage (primary) throttle closed.
  2.  
  3. Turn the first stage throttle valve stop screw until there is a gap between it and the lever moves.
  4.  
  5. Turn the screw in until it just touches the lever.
  6.  
  7. Turn screw in 1 / 4 turn more.
  8.  
  9. Adjust the idle speed and fuel mixture.
  10.  



Click image to see an enlarged view

Fig. Fig. 5: First stage throttle gap adjustment point (arrow)

To adjust the second stage (secondary) throttle gap, proceed as follows:

  1. The choke must be open and the first stage throttle must be closed.
  2.  
  3. Turn the second stage (secondary) adjusting screw until there is no clearance in the lever it is mounted on.
  4.  
  5. From this position, turn the screw out 1 / 4 turn. There should be noticeable clearance at the lever.
  6.  



Click image to see an enlarged view

Fig. Fig. 6: Second stage throttle gap adjustment (A)

FUEL LEVEL

See Figure 7

Remove the top of the carburetor. You may not have to remove the entire carburetor from the engine to perform this operation.

  1. With the carburetor top upside down and canted at a 45 degree angle (to prevent the damping ball in the needle valve from settling too deeply due to the weight of the float), measure from the highest tip of the first stage float to the carburetor surface (minus the gasket). The distance for the first stage float should be 1.08-1.12 in. (27.5-28.5mm)
  2.  



Click image to see an enlarged view

Fig. Fig. 7: Checking the float level

  1. Adjust the second stage float in the same manner. The distance for the second stage float should be 1.18-1.22 in. (29.5-30.5mm).
  2.  
  3. Adjust the float level by bending the float bracket.
  4.  

If the float height must be adjusted, remove the float from the carburetor to prevent damage to the needle valve.

FAST IDLE

See Figure 8

It will be necessary to remove the carburetor from the engine to perform this procedure.

  1. Turn the carburetor upside down and drain the fuel from it.
  2.  
  3. With the carburetor upside down, close the choke tightly and measure the gap between the lower edge of the throttle valve and the housing wall with a drill. The measurement should be 0.018-0.020 in. (0.45-0.50mm).
  4.  
  5. Adjust the gap at the adjusting screw (beside the first stage valve) which is facing up when the carburetor is upside down.
  6.  



Click image to see an enlarged view

Fig. Fig. 8: Fast idle adjustment gap (A) and adjuster screw (B)

CHOKE VALVE GAP

See Figures 9 and 10

  1. Remove the automatic choke cover. You should be able to remove the cover without unfastening the water hoses.
  2.  
  3. Open and close the choke to make sure its internal spring is working. If not, remove the vacuum cover at the side of the choke assembly and check the spring.
  4.  
  5. Push the choke lever to its stop (arrow A) and hold the rod there with a rubber band.
  6.  
  7. Equalize the bushing and lever clearances by pushing the choke valve slightly open (arrow B).
  8.  



Click image to see an enlarged view

Fig. Fig. 9: Checking the choke gap

  1. Check the choke gap with an appropriate size drill. The gap should be between 0.152-0.168 in. (3.8-4.2mm).
  2.  
  3. Adjust the choke valve gap by turning the screw in the end of the vacuum unit at the side of the choke assembly. Lock the adjusting screw by dabbing a little paint or thread sealant over its end.
  4.  



Click image to see an enlarged view

Fig. Fig. 10: Choke valve gap adjusting screw

When installing the automatic choke cover, the choke lever (protruding part) must fit in the loop on the coiled spring.

AUTOMATIC CHOKE

Align the mark on the automatic choke cover with the mark on the carburetor by loosening the three retaining across and turning the choke with the hoses still attached.

DASHPOT

See Figure 11

The purpose of the dashpot is to keep the throttle from snapping shut and stalling the engine. The dashpot has a plunger that extends when the throttle is closed suddenly. The plunger contacts a tab on the throttle lever and holds the throttle open slightly for a second, then closes the throttle slowly over the period of another second or so.

Not all models are equipped with dashpots.

  1. Close the throttle valve and make sure the choke is fully open. You may have to run the car up to the operating temperature.
  2.  
  3. Push the plunger in as far as it will go and measure the gap between the end of the plunger and its striking surface. The gap should be 0.122 in. (3mm).
  4.  



Click image to see an enlarged view

Fig. Fig. 11: Checking the dashpot gap

  1. Adjust by loosening the lock nut and moving the dashpot on its threads.
  2.  

Zenith 2B2 Carburetor
THROTTLE GAP

See the Zenith 2B3 section for throttle gap adjustment procedures.

FUEL LEVEL

This fuel level adjustment procedure is the same as that for the Zenith 2B3 carburetor.

FAST IDLE-1975

See the 2B3 carburetor section for fast idle gap adjustment on 1975 models.

FAST IDLE-1976

See Figure 12

On these models it is not necessary to remove the carburetor. The engine must be at normal operating temperature.

  1. Set the ignition timing.
  2.  
  3. Disconnect and plug the hose from the choke pull-down unit.
  4.  
  5. Open the throttle valve slightly and close the choke valve.
  6.  
  7. Close the throttle valve. The choke valve should be fully open again.
  8.  
  9. Set the stop screw of the fast idle cam on the highest step. Start the engine.
  10.  
  11. Adjust the speed with the screw (arrow) to 3,150-3,250 rpm on manual transaxles, or 3,350-3,450 rpm on automatic transaxles.
  12.  



Click image to see an enlarged view

Fig. Fig. 12: Fast idle adjustment

CHOKE GAP

See Figure 13

  1. Remove the automatic choke cover.
  2.  
  3. Close the choke valve and push the choke rod to the stop (arrow).
  4.  
  5. Hold the choke in position with a rubber band (a).
  6.  
  7. Push the choke lever (b) down slightly to equalize the clearances.
  8.  
  9. Check the choke gap between the edge of the carburetor wall and the edge of the valve with a drill. It should be:

    1975-0.19 in. (4.8mm) with vacuum delay valve
     
    1976-0.14 in. (3.5mm) with primary activated; 0.20 in. (5.0mm) with secondary activated
     

  10.  
  11. Adjust the gap by turning the screw on the choke vacuum unit in to decrease the gap or out to increase the gap.
  12.  



Click image to see an enlarged view

Fig. Fig. 13: Choke gap adjustment screw

AUTOMATIC CHOKE

Align the mark on the automatic choke cover with the mark on the carburetor.

AUTOMATIC CHOKE TEMPERATURE SWITCH

The temperature switch must be removed from the carburetor and checked with an ohmmeter. Connect an ohmmeter across the 2 terminals. It should read 0 ohms below 107°F (42°C), and infinite resistance above 136°F (58°C).

DASHPOT

Dashpot adjustments are the same as those for Zenith 2B3 carburetor.

Solex 34 PICT-5-1978 Models
THROTTLE VALVE (BASIC SETTING)

See Figure 14

You need a vacuum gauge to set the throttle valve. The stop screw is set at the factory, and should not be moved. If the screw is accidentally turned, proceed as follows.

  1. Run the engine at idle.
  2.  
  3. Remove the vacuum advance hose at the carburetor and connect a vacuum gauge.
  4.  
  5. Remove the plastic screw cap and turn the stop screw in until the gauge indicates vacuum.
  6.  
  7. Turn the stop screw out until the gauges indicates no vacuum. Turn the screw an additional 1 / 4 turn and install the plastic cap.
  8.  
  9. Adjust the idle and fuel mixture.
  10.  



Click image to see an enlarged view

Fig. Fig. 14: Throttle valve basic adjustment stop screw location

CHOKE VALVE

See Figure 15

  1. Remove the cover from the automatic choke and fully close the choke.
  2.  
  3. Push the choke rod in the direction of the arrow (1) and check the gap between the choke valves and the air horn wall. It should be 0.11-0.13 in. (2.8-3.3mm).
  4.  
  5. If necessary, change the gap by turning the adjusting screw (2).
  6.  



Click image to see an enlarged view

Fig. Fig. 15: Adjusting the choke valve

  1. Reassemble the choke cover. There is an index mark on the choke housing and another on the choke cover.
  2.  

FAST IDLE

See Figure 16

The engine should be at normal operating temperature.

  1. Run the engine with the screw on the 3rd step of the fast idle cam. The speed should be 2,350-2,450 rpm. Adjust this speed with the adjusting screw.
  2.  
  3. Stop the engine. Open the choke valve fully and check the gap between the adjusting screw and fast idle cam (arrow). It should be 0.008 in. (0.20mm).
  4.  



Click image to see an enlarged view

Fig. Fig. 16: Checking the fast idle gap

ALTITUDE CORRECTION

See Figure 17

Cars that are generally operated 3,600 feet (1,097 meters) above sea level may require altitude correction, which is made by backing out the two screws (arrows) until they are flush with the carburetor body. Adjust the idle and fuel mixture.



Click image to see an enlarged view

Fig. Fig. 17: Altitude adjustment screws

Solex 34 PICT-5-1980 Models

See Figures 18 and 19

PART THROTTLE HEATER

This carburetor is equipped with a heating element which partly pre-heats the throttle channel while the engine temperature is below 167°F (75°C). This allows the engine to run smoother during warm-up time and prevents excessive use of the choke valve.

To test the part throttle heater, disconnect its wire and connect a test light between the throttle heater lead and the positive battery terminal. The heating element is working if the test light lights up. If the light fails to light, the element is bad and must be replaced.

MAIN JET SHUT-OFF SYSTEM

The shut-off valve is vacuum activated by the vacuum control unit, located on the fender inside the engine compartment next to the brake master cylinder. A relay is activated via terminal 15 of the fuse panel and shuts off the fuel flow to the main jet if voltage is less than 5 volts at terminal 15 or when the ignition is cut-off. Test the system as follows:

  1. Run the engine at idle and disconnect the electrical connector from the front of the vacuum control unit.
  2.  
  3. The engine should stall. If not, check the vacuum tubes for blockage and check the vacuum control unit. If these are not the problem, replace the main jet cut-off valve.
  4.  



Click image to see an enlarged view

Fig. Fig. 18: Part throttle heater connection (1), thermoswitch 1 (2), thermoswitch 2 (3), choke heater connection (4). Arrow indicates the idle jet

IDLE SHUT-OFF VALVE
  1. Run the engine at idle.
  2.  
  3. Pull the electrical connector from the idle shut-off valve.
  4.  
  5. The engine should stall. If not, replace the idle shutoff valve.
  6.  



Click image to see an enlarged view

Fig. Fig. 19: Cold start valve (1), main jet cutoff valve (2), idle shutoff valve (3)

AUTOMATIC CHOKE

The automatic choke is operated by the electrical heating element inside the choke and coolant temperature. When coolant temperature is below 61°F (16°C), the electrical heating element in the choke receives current from thermoswitch 1 and the resistor wire. Approximately 9 volts of current is applied at this point.

When the engine temperature (coolant) is between 61°F (16°C) and 167°F (75°C), the resistor wire is bypassed by thermoswitch 2 and the heating element in the choke receives full battery voltage (12 volts).

When the coolant temperature exceeds 167°F (75°C), all electrical activation of the choke valve is switched off, thermoswitch 1 opens interrupting the current to the heating element while the choke fully opens. To test the choke system, proceed as follows:

  1. Unplug the choke heating element connector and connect the positive lead of a voltmeter to the female part of the connector (part leading into the wiring harness). Connect the negative lead of the voltmeter to the carburetor ground wire. Turn the ignition ON .
  2.  
  3. With the coolant temperature below 59°F (15°C), record the voltage.
  4.  
  5. Run the engine up above 131°F (55°C) and check the voltage again. Compare the two readings. The first reading should be one or two volts below the second reading.
  6.  
  7. With the engine at operating temperature (the cooling fan must have come on at least once), the voltmeter should have no reading. If it does, check the thermoswitches.
  8.  

To test the thermoswitches, remove the switches and connect an ohmmeter between the terminals on each thermoswitch. Thermoswitch 1 opens when the temperature reaches 167°F (75°C) and closes when the temperature drops to 149°F (65°C). Thermoswitch 2 closes when the temperature reaches 131°F (55°C) and opens when the temperature drops to 61°F (16°C).

CHOKE VALVE GAP
  1. Set the cold idle speed adjuster screw in its upper notch.
  2.  
  3. Connect a manually operated vacuum pump to the connection on the pulldown unit and build up vacuum.
  4.  
  5. Close the choke valve by hand with the lever and check the choke valve gap with a drill. The gap should be 0.123-0.146 in. (3.0-3.7mm).
  6.  
  7. Adjust the gap using the adjusting screw on the pulldown unit. After adjusting, lock the screw with sealant or a dab of paint.
  8.  

FAST IDLE SPEED
  1. Run the engine up to operating temperature and make sure the ignition setting and the idle adjustment are correct.
  2.  
  3. Run the engine at idle and set the adjusting screw on its third notch on the choke valve lever.
  4.  
  5. Open the choke valve fully by hand using the choke valve lever.
  6.  
  7. Connect a tachometer and check the rpm.
  8.  

See Electronic Ignition Precautions in Engine Performance And Tune-up for warning about connecting tachometers to electronic ignition systems.

  1. The fast idle speed should be between 2,350-2,450 rpm. If not, adjust with fast idle adjustment screw. Lock screw with safety cap after adjustment.
  2.  

COLD START VALVE

The cold start valve enriches the air/fuel mixture when engine temperature is below 60°F (15°C) by injecting fuel into the throttle chamber through a passage parallel to the main jet. Test the valve for continuity with an ohmmeter. The ohmmeter should display approximately 80 ohms. If it reads infinite resistance, replace the valve.

THROTTLE KICKER

The throttle kicker increases the idle speed to prevent stalling when the air conditioner is engaged. To test, proceed as follows:

  1. Run the engine up to operating temperature and check the ignition timing. Unplug the ignition advance idle stabilizer and connect the two plugs together (if equipped). Remove the retard and advance vacuum hoses and plug them. Make sure the basic idle speed and mixture adjustments are correct.
  2.  
  3. Reconnect the advance and retard hoses and reconnect the plugs for the idle stabilizer.
  4.  
  5. Rev the engine to start the idle stabilizer and note the ignition timing at idle.
  6.  
  7. Switch on the air conditioner (coldest temperature setting, highest fan speed), the ignition timing should not change.
  8.  
  9. If the timing changes, adjust the throttle kicker screw where it contacts the throttle valve lever until the correct setting (no timing change) is reached. Seal the screw with Loctite® or equivalent sealant.
  10.  

VACUUM CONTROL UNIT

See Figures 20 and 21

The vacuum control unit has two functions. It houses both the relay for the main jet cutoff valve and the relay for the throttle kicker on air conditioner equipped vehicles.

To test the main jet cutoff valve relay, perform the steps under the heading Main Jet Cutoff Valve. If the engine continues to run and you are sure the vacuum lines are not clogged and the valve is working replace the relay inside the vacuum control unit.



Click image to see an enlarged view

Fig. Fig. 20: Vacuum control unit location (arrow)

To test the throttle kicker relay, run the engine and turn the air conditioner on and then turn it off. The kicker should move in and out. If it doesn't connect the vacuum retard hose from the distributor to the throttle kicker vacuum connector. If the kicker moves, replace the relay. If the kicker does not move, replace the throttle kicker.



Click image to see an enlarged view

Fig. Fig. 21: Internal view of the vacuum control unit. Main jet cutoff valve relay (A) and throttle kicker relay (B). The throttle kicker relay is used on air conditioned cars

Carter TYF Carburetors
THROTTLE GAP

Throttle gap is set at the factory and should not be tampered with.

FAST IDLE
  1. Run the engine until it reaches normal operating temperature. Make sure that the timing and idle speed are set to specifications.
  2.  
  3. Run the engine at idle and set the fast idle adjustment screw to the second step of the fast idle cam.
  4.  
  5. Disconnect the purge valve. Disconnect and plug the vacuum hose at the EGR valve.
  6.  
  7. Connect a tachometer as per the manufacturer's instructions and check that the engine speed is 2,800-3,200 rpm. If not, turn the fast idle screw until it is.
  8.  
  9. Reconnect the purge valve and the vacuum hose at the EGR valve.
  10.  

CHOKE GAP
  1. Set the cold idle speed adjuster screw in its upper notch.
  2.  
  3. Connect a manually operated vacuum pump to the connection on the pulldown unit and build up vacuum.
  4.  
  5. Close the choke valve by hand with the lever and check the choke valve gap with a drill. The gap should be 0.154 in. (4.0mm) for 1982 models and 0.165 in. (4.2mm) for l983 models.
  6.  
  7. Adjust the gap using the adjusting screw in the end of the vacuum unit at the side of the choke unit. After adjusting, lock the screw with sealant.
  8.  

THROTTLE LINKAGE ADJUSTMENT



All Carbureted Models

Throttle linkage adjustments are not normally required. However, it is a good idea to make sure that the throttle valve(s) in the carburetor open all the way when the accelerator pedal is held in the wide-open position. Only the primary (first stage) throttle valve will open when the pedal is pushed with the engine off: the secondary throttle on Volkswagen 2-barrel carburetors is vacuum operated. Make note of the following:

  1. Always be careful not to kink or twist the cables during installation or adjustment. This can cause rapid wear and binding.
  2.  
  3. On the Rabbits and Sciroccos, the accelerator cable will only bend one way; make sure you install it with the bends in the right positions.
  4.  
  5. On 1974-75 Dashers, when installing new accelerator cable, the hole in the firewall must be enlarged to 5 / 8 in. (16mm). Adjust these cables at the pedal clamp.
  6.  

When installing new cables, all bends should be as wide as possible, and fittings between which the inner cable is exposed must be aligned.

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner.
  4.  
  5. Disconnect and plug the fuel lines.
  6.  
  7. Drain the coolant to below the level of the choke hoses, then disconnect them.
  8.  
  9. Disconnect and label all vacuum lines.
  10.  
  11. Disconnect and label all electrical leads.
  12.  
  13. Remove the clip which secures the throttle linkage to the carburetor. Detach the linkage, being careful not to lose any washers or bushings.
  14.  
  15. Unbolt the carburetor from the manifold and remove it. If the carburetor is to be left off the engine for any length of time, cover the intake manifold opening with masking tape to prevent anything from falling into the engine.
  16.  

To install:
  1. Clean the carburetor and intake manifold surfaces and lay the new gasket onto the intake manifold. ALWAYS use a new gasket.
  2.  
  3. Set the carburetor on top of the gasket and tighten the nuts in a crisscross pattern until snug. Don't overtighten.
  4.  
  5. Connect and adjust the throttle linkage.
  6.  
  7. Connect the electrical leads and vacuum lines.
  8.  
  9. Connect the choke hoses.
  10.  
  11. Connect the fuel lines.
  12.  
  13. Install the air cleaner and fill the cooling system to the proper level.
  14.  
  15. Connect the battery cable.
  16.  

OVERHAUL



See Figures 22 and 23

Specific directions and specifications for carburetor overhaul are usually contained in the rebuilding kit.

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. Keep all similar and look-alike parts segregated during disassembly and cleaning to avoid accidentally 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 and be sure that there are no restrictions or blockages. Never use wire or similar tools to clean jets, fuel passages, or air bleeds. Clean all jets and valves separately to avoid accidental interchange.



Click image to see an enlarged view

Fig. Fig. 22: Exploded view of the Carter TYF carburetor



Click image to see an enlarged view

Fig. Fig. 23: Exploded view of the Solex 32/35 carburetor

Check all 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.  
  3. Check the float hinge pin for wear and the float(s) for dents or distortion. Replace the float if fuel has leaked into it.
  4.  
  5. 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 adversely affect starting and idling.
  6.  
  7. 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.
  8.  
  9. 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.
  10.  
  11. Check the bowl cover for warped surfaces with a straightedge.
  12.  
  13. Closely inspect the valves and seats for wear and damage, replacing as necessary.
  14.  
  15. After the carburetor is assembled, check the choke valve for freedom of operation.
  16.  

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
 
All diaphragms
 
Spring for the pump diaphragm
 

Major Repair Kits


All jets and gaskets
 
All diaphragms
 
Float needle valve
 
Pump ball valve
 
Float
 
Complete intermediate rod
 
Intermediate pump lever
 
Some cover hold-down screws and washers
 

Gasket kits contain all gaskets.

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.

 
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