Carburetor with automatic choke
Fast idle
1. Check that the idle speed meets the requirements (see previous section).
2. Remove the air cleaner and plug the end of the vacuum hose that normally connects to the vacuum capsule in the air cleaner.
3. Turn off the ignition.
4. Open the throttle valve slightly so that you can rest the fast idle speed screw on the second highest shoulder of the cam (see Fig.3.10).
5. Without pressing the gas pedal, start the engine. The fast idle speed must be within the specified limits. If not, adjust them using the fast idle speed screw (see photo 10.1A).
Lowering adjustment (discoveries) air damper (gap A)
b. In order to adjust this gap, you will need a vacuum pump. Sufficient vacuum can be obtained by using a converted hand pump or by connecting a hose or plastic tube between the carburetor vacuum block and the intake manifold of another car whose engine must be running.
7. Remove the air cleaner.
8. Install the fast idle screw on the upper cam shoulder. Check that the air damper is completely closed. If it has not yet closed, secure it in the closed position using a rubber ring (see fig. 3.11).
9. Apply vacuum to the choke vacuum unit (see paragraph 6).
10. Measure the gap "A" between the edge of the choke and the wall of the carburetor (see fig. 3.12) (measurements are taken from the working side of the damper). The gap must be as specified.
Pic. 3.10. Fast idle screw (shown by arrow) rests on the second highest shoulder of the cam (2)
11. Gap "A" can be adjusted with a screw "IN". If the gap is too small, the rod may need to be bent slightly to provide enough room for the adjusting screw to move.
Pic. 3.11. Secure the air damper in the closed position using a rubber ring
12. Upon completion of the adjustment, lock the adjustment screw by dripping paint or glue onto it.
Pic. 3.12. Checking the gap between the edge of the valve and the carburetor wall: A. See Specifications; B. Adjustment screw on the vacuum block.
13. Check the gap between the deflector lever and the rod with the vacuum still applied, i.e. when the rod is extended to its maximum length (see Fig.3.13). Required gap size "A" shown in the figure. If necessary, adjust the gap by bending the rod accordingly. Adjusting the air damper for fast idle speed (gap "IN")
Pic. 3.13. Gap between deflector and rod: A = 0.1-0.3 mm.
14. Secure the air damper in the closed position with a rubber ring (see fig. 3.11).
Pic. 3.14. To adjust the air damper gap, bend the tongue "G"
15. Open the throttle valve and set the fast idle speed screw to the second highest shoulder of the cam. Release the throttle and check that the screw remains on the ledge.
Pic. 3.15. Adjusting the gap between the lever and the accelerator pump rod: A = 7.8-8.2 mm.
16. Open the choke slightly and release it until it moves into the correct position on its own. Check the gap "IN" in the same way as when checking the gap "A".
Pic. 3.16. Measuring the top position of the float
17. If necessary, adjust the gap "IN" remove the carburetor. Remove the choke cover and bend the rod connecting the fast idle cam to the choke lever until the correct clearance is achieved.
Pic. 3.17. Adjusting the upper position of the float: 1. Bend at the indicated points.
18. After installing the carburetor in place, check the clearance of the lowered choke again (gap "A").
Pic. 3.18. Adjusting the Varajet carburetor choke cable with manual choke: 1. Spring retaining clip; 2. Inner cable clamp; 3. Outer cable clamp.
Adjusting the choke at full throttle (gap "WITH")
19. Secure the air damper in the closed position with a rubber ring. Fully open the throttle valve and keep it open while measuring the clearance "WITH".
Pic. 3.19. On the latest models of the Varajet carburetor, a special valve can be installed (shown by arrow) to prevent the engine from missing the flash
20. If it is necessary to adjust the gap, bend the tongue shown in Fig. 3.14. Bending the tongue to the right increases the gap, to the left - decreases it.
Pic. 3.20. Throttle valve damper on Varajet carburetor: A. Damper pin; B. Locknut.
Automatic choke cover
21. The pointer on the choke housing cover must be set to the central position. If during warm-up the engine stalls or runs unstably, you can turn the cover 1-2 notches towards the letter "R" (rich mixture).
Pic. 3.21. Adjustment screw (shown by arrow) Varajet carburetor partial load systems
22. When starting the engine cold, it should take 2-3 minutes for the choke to fully open. If this process takes longer, the choke cap should be replaced and the choke should be checked for freedom of movement.
Acceleration pump
23. With the air cleaner removed, check that the throttle lever is in the idle position with the engine at normal operating temperature. Turn off the engine.
24. Manually smoothly move the throttle valve to the fully open position, while simultaneously monitoring the fuel supply from the pump nozzle. Fuel must flow continuously, without interruption, throughout the entire stroke of the pump piston. If this is not the case, the pump should be disassembled and worn seals replaced.
25. Using a screwdriver, press the pump rod until it stops, and then measure the gap between the end of the lever and the rod (see fig. 3.15). The gap should not go beyond the specified limits. It can be adjusted by bending the pump lever.
Top float position
26. Remove the carburetor cover.
27. Manually apply pressure to the float arms and float shaft clamp to hold the fuel inlet needle valve in the closed position.
28. The top surface of the float must be at a specified distance from the top flange of the carburetor (see fig. 3.16).
29. If necessary, bend the float arms equally at the points shown in Fig. 3.17.
Carburetor with manual choke
Lowering adjustment (discoveries) air damper
30. Remove the air cleaner.
31. Pull out the choke handle so that the mark on the cam aligns with the central part of the fast idle speed screw.
32. Apply vacuum to the carburetor vacuum unit. To do this, you can use a hand suction pump or connect the vacuum unit with a hose or plastic tube to the intake manifold of another car whose engine is idling.
33. Check the gap between the edge of the air damper and the wall of the carburetor air neck (To measure the gap, you can use a drill of the required size - see Specifications).
34. If necessary, you can adjust the gap using the adjusting screw (see fig. 3.12). If the gap is too small to be adjusted, adjust the rod end fitting accordingly.
Fast idle
35. Stop the engine at normal operating temperature and remove the air cleaner.
36. Plug the end of the thin hose that was disconnected from the air cleaner and connected it to the carburetor.
37. Pull out the choke handle so that the mark on the cam aligns with the central part of the fast idle speed screw.
38. Hold the choke open manually or secure it with a rubber ring.
39. Start the engine and check that the fast idle speed is consistent Specifications. To check the speed, you can use the vehicle's tachometer or connect a temporary tachometer according to the manufacturer's instructions.
40. Fast idle speed is adjusted using the fast idle speed screw (see photo 10.1A).
Adjusting the choke cable
41. An incorrectly adjusted cable can prevent the primary throttle from fully opening and completely disable the secondary throttle, preventing the engine from developing normal power when it reaches operating temperature.
42. Adjust the cable as follows.
43. Loosen the clamping screws on the outer and inner cables.
44. Push the choke handle inward until it stops (position of the suction completely switched off) so that the regulator snaps into place with the spring locking clip.
45. Place the outer cable so that it stands in its clamp without distortions or tension, and tighten the screw.
46. Tighten the clamp screw on the inner cable.
47. Check the cable for freedom of movement throughout the entire range and make sure that when the choke regulator is snapped into place with a spring clip, it is set to the position corresponding to the choke being completely turned off (see fig. 3.18).
Carburetors with manual and automatic choke
Throttle Actuator Damper - Automatic Transmission Models
48. Models with an automatic transmission may be equipped with a throttle damper, the purpose of which is to prevent the throttle from slamming suddenly when the gas pedal is released.
49. The damper is adjusted as follows. Loosen the damper locknut and turn it out so that its pin just touches the throttle lever. From this position, screw the damper inward 3-4 full turns and secure it with a lock nut (see fig.3.20). Part load adjustment screw
50. Jerking or slow response of the machine when opening the throttle slightly, as well as excessive fuel consumption during gentle driving, can be caused by incorrect adjustment of the partial load mode screw.
51. Do not begin adjusting this screw until you are sure that the above problems cannot be caused by any other causes.
52. Remove the carburetor from the car.
53. Pry up and remove the metal plug covering the partial load mode adjusting screw (located next to the fuel inlet fitting - see fig. 3.21).
54. If the problem is jerking or slow response of the machine (those. the mixture is too lean), turn the screw 1/4 turn counterclockwise.
55. If the problem is excessive fuel consumption (mixture too rich), the screw must be turned 1/4 turn clockwise.
56. Reinstall the carburetor and test drive it to see if the problem is resolved. Additional adjustments can be made if necessary, but be careful not to move the screw more than 1/2 turn from its original position.
57. When finished, install a new metal plug.
Other adjustments
58. The accelerator pump and the upper position of the float are adjusted in the same way as in the case of a carburetor with automatic choke (see above in the same section).
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