Figure 14.3. Carburetor equipped with an automatically controlled air damper: 1 – primary chamber air jet; 2 – primary chamber economizer and economizer atomizer; 3 – secondary chamber air jet; 4 – secondary chamber economizer and economizer atomizer; 5 – needle valve; 6 – float; 7 – main jet of the primary chamber; 8 – screw for adjusting the quality of the fuel-air mixture; 9 – plug; 10 – secondary chamber main jet; 11 – plug; 12 – secondary chamber idle jet; 13 – carburetor body; 14 – carburetor base; 15 – bolt (with a vacuum channel); 16 – secondary chamber diaphragm; 17 – damper rod; 18 – electromagnetic valve for idle fuel cut-off; 19 – balancing channel; 20 – air jet of the primary chamber of the idle system (No. 2); 21 – primary chamber idle jet; 22 – plug; 23 – accelerator pump check valve; 24 – accelerator pump; 25 – spring; 26 – air damper with automatic control; 27 – lever; 28 – air neck; 29 – screw
The carburetor on later models with the 2.0L engine features an automatic choke instead of the manual choke found on earlier models. The damper drive consists of a bimetallic spring, which is heated by an electric current and opens the air damper for a time, the duration of which depends on the air temperature (figure 14.3).
Apart from the presence of an automatically controlled air damper, the design of the carburetor is practically no different from the design of the carburetor of earlier years of production.
Automatically controlled air damper
Removal and installation
Remove the air filter and disconnect the power wire from the automatic choke.
Remove the screws, remove the cover and at the same time disconnect the bimetallic spring from the damper drive lever.
Figure 14.4. Alignment of marks (1)
Installation is carried out in the reverse order of removal; before tightening the screws, align the mark on the cover with the center mark on the body (figure 14.4).
Checking and adjusting
Check the conductivity of the heating coil of the automatic air damper by disconnecting the power wire from it and connecting the ohmmeter probes to the coil wire and the vehicle ground. If the ohmmeter shows "infinity", then there is a break in the winding and the air damper cover must be replaced.
The operation of adjusting the diaphragm of the damper is similar to the operation given in the subsection "Carburetor repair and adjustment".
Figure 14.5. Idle speed system clearance adjustment elements (G): 1 – idle system cam; 2 – adjusting screw; 3 – idle speed control lever
To adjust the throttle opening at idle, open the throttle, lower the lever to the second upper stage of the cam. Check the clearance between the primary chamber throttle valve and the wall; it should be 0.94–1.38 mm. If necessary, adjust it by turning the adjusting screw (figure 14.5).
Data provided by the website: Mazbook
The operation for checking the throttle valve opening is similar to the operation given in the subsection "Carburetor repair and adjustment" (see "Gasoline engine fuel system"), but the primary chamber valve must be open by 50° before the secondary chamber valve begins to open. Nominal size 7.32–8.28 mm.
Figure 14.6. Location for measuring the throttle valve clearance (R) when the engine is idling: a – adjusting tongue
To adjust the throttle opening with the engine idling, open the throttle valve and lower the lever to the second upper cam position (figure 14.6). Check that the gap between the top edge of the throttle valve and the wall is between 0.60 and 1.00 mm. If minor adjustments are needed, bend the tab on the drive lever. If significant adjustment is required, bend the drive rod.
Figure 14.7. Carburetor relief valve clearance (R) adjustment elements: a – adjusting tongue
To adjust the relief valve, fully open the primary chamber throttle valve, then check that the gap between the upper edge of the primary chamber throttle valve and the wall is 0.07–0.51 mm; bend the tongue if necessary (figure 14.7).
To check the throttle operation at idle, warm up the engine to normal operating temperature, then stop it and remove the air filter. Open the throttle valve slightly, then close the throttle valve completely and release the throttle valve. The idle cam will hold the primary throttle valve open in the idle position. Connect a tachometer, then, without pressing the accelerator pedal, start the engine and ensure that the engine speed is between 3000 and 4000 rpm. If necessary, adjust the engine speed by turning the idle speed adjusting screw. Stop the engine, disconnect the tachometer and reinstall the air filter.