Contents: Increased idle speed ↓ Air Damper Starting Gap - Stage 1 ↓ Air Damper Starting Gap - Stage 2 ↓ Combining the housing and cover of…↓ Accelerator pump ↓
Adjustment of idle speed and CO content in exhaust gases is described in the chapter "Engine adjustment". Remove the air filter and adjust the carburetor as follows:
Increased idle speed
1. Connect a tachometer to the engine.
2. Plug the vacuum hose of the air filter thermostat (air filter removed).
3. Remove the tee (A) from the vacuum hose (B) - Figure G:21 - and plug the hose.
4. Start the engine and measure the high idle speed value.
5. If the idle speed is outside the limits specified in section "Technical data", adjust them by turning the adjusting screw (A, figure W:22).
6. Connect the vacuum hose, adjust the idle speed if necessary (see chapter "Engine adjustment").
7. Fix the adjusting screw (A) with paint.
Initial position of the throttle valve (basic adjustment) — primary chamber.
The throttle valve limit screw position is factory set and should not be changed. The initial throttle valve position should only be adjusted if the screw position has been changed.
1. Turn the heating mode control cam (A, figure W:23) so that the pin (B) on the throttle lever does not touch the cam.
2. Lock the cam in this position using a screwdriver (D) by inserting it between the cam and the lever (C).
3. Remove the hoses from the three vacuum drive pipes and plug the pipes (B, figure W:24).
4. Connect the vacuum pump to the pipe (A, figure W:24) and create the vacuum necessary to hold the diaphragm in the throttle closing position.
5. Make sure there is clearance between the high idle speed adjustment screw and the diaphragm plunger.
6. Loosen the limit screw (A, figure W:25) so that between it and the throttle limiter (B, figure G.25) a gap appeared.
7. Tighten the screw until it touches the stop.
8. Tighten the adjusting screw another 1/4 turn and seal its threads with paint.
Initial position of the throttle valve (basic adjustment) - secondary chamber.
The throttle position is factory set and should not be changed. The initial throttle position should only be adjusted if the setting has been changed.
1. Remove the carburetor as described earlier in this chapter.
2. Fully open the throttle valve of chamber I and firmly fix it in this position (A, figure W:28).
3. Using a rubber band, tighten the throttle lever of the I camera (B, figure W:28).
4. Loosen the limit screw (C) so that a gap appears between the screw and the stop (D, figure W:28).
5. Tighten the limit screw until it touches the stop.
6. Tighten the limit screw another 1/4 turn.
7. Release both throttle valves and check the clearance in the throttle actuator mechanism (E and F, figure G:28).
8. Adjust the gap by bending the lever (shown by arrow), if the gap value is outside the limits specified in the section "Technical data".
Air Damper Starting Gap - Stage 1
1. Remove the automatic air damper cover.
2. Turn the choke lever clockwise and secure it in this position with a rubber band.
3. Remove the vacuum hose from the carburetor and attach a vacuum pump in its place (B, figure G:22 and A, figure G:24).
4. Remove the vacuum hose (C, figure W:26), but don't drown it out.
5. Create and maintain a vacuum of 200-300 mbar.
6. Check the air damper clearance using a drill bit of the appropriate diameter (D, figure W:26).
7. If the gap is outside the limits specified in section "Technical data", adjust it with the Allen screw (B, figure W:26). Cover the adjusting screw with paint.
Air Damper Starting Gap - Stage 2
1. Plug the vacuum hose (E, figure W:26).
2. Create a vacuum of 200 mbar using a vacuum pump.
3. Check the air damper clearance with a drill (B, figure W:27).
4. If the gap is outside the limits specified in section "Technical data", adjust it with the screw (C, figure W:27).
5. Cover the screw with paint.
Combining the housing and cover of the air damper drive
The marks on the body and cover of the air damper drive must be aligned.
Accelerator pump
1. Connect the vacuum pump to the vacuum drive pipe (A, figure W:24).
2. Plug the open vacuum hose (B, figure W:24).
3. Create the vacuum necessary to hold the diaphragm in the closed throttle position. There should be an air gap between the high idle speed adjusting screw and the diaphragm pushrod.
4. Turn the warm-up control lever so that the throttle lever pin does not touch it.
5. Secure the warm-up mode control lever in this position by inserting an M8x20 bolt between the lever and the carburetor body.
6. Place a measuring container under the carburetor mixing chamber to collect the fuel.
7. Open and close the throttle valve five times within 15 seconds.
8. Measure the amount of fuel that has entered the container, divide this value by 5 and compare the obtained value with the one specified in the section "Technical data".
9. If the pump performance is not within the specified limits, loosen the clamp screw (A, figure W:29) and adjust the pump by turning the high idle cam (B). After adjustment, install the carburetor on the engine and check the idle speed and CO content (see "Engine adjustment").
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