Recommendation: When making carburetor adjustments, use a specialized tool.
1. Adjust the full throttle opening angle of the primary chamber of the carburetor.
- Nominal angle - 90°from horizontal
Adjust if necessary by bending the throttle stop.
2. Adjust the angle of full opening of the throttle valve of the secondary chamber of the carburetor.
(carburetor option with an additional damper in the secondary chamber)
A) With the secondary throttle lock lever deflected, fully open the secondary throttle and check the opening angle, which is nominally: 90°from horizontal.
b) If necessary, adjust by bending the throttle valve limiter of the secondary chamber.
(variant without additional damper in the secondary chamber)
A) With the primary throttle wide open, open the secondary throttle and check its full opening angle.
- Nominal angle - 80°from horizontal
b) If necessary, adjust by bending the throttle valve limiter of the secondary chamber.
3. (variant without additional damper in the secondary chamber) Adjust the secondary throttle forced opening angle when the primary throttle is wide open.
A) With the primary throttle wide open, check the clearance between the secondary throttle and the carburetor body (mixing chamber body).
- Nominal clearance for carburetors - 0.20 mm
b) If necessary, adjust by bending the lever for forced opening of the throttle valve of the secondary chamber.
4. Adjust the primary throttle angle to match the opening of the secondary throttle.
A) Check the primary throttle opening angle at which the secondary throttle starts to open, that is, the moment the primary throttle push lever touches the secondary throttle push lever.
- The nominal angle from the horizontal plane is - 50°
b) If necessary, adjust by bending the pressure lever of the throttle valve of the secondary chamber:
5. (Auto choke carburetors)
Install an automatic choke.
A) Align the mark on the spring housing with the center line of the thermostat housing as shown.
Attention: the air damper closes completely at an ambient temperature of: 15°C
b) Depending on the operating conditions of the vehicle, rotate the spring housing and adjust the composition of the mixture when starting the engine:
- if the mixture is too "rich" - turn clockwise;
- if the mixture is too "poor" - turn counterclockwise.
6. Pre-set the throttle valve to the position corresponding to the increased idling speed when the engine warms up.
(Carburetor with automatic choke)
A) Install the high idle warm-up cam. To do this, while holding the throttle ajar, close the choke and, while holding it closed, release the throttle.
With the choke valve closed, check the throttle valve opening angle.
- The nominal angle from the horizontal plane is for the carburetor - 20 - 22°
b) If necessary, adjust the amount of mixture of the high idle system during warm-up by turning the adjusting screw.
7. (Carburetor with automatic choke)
Adjust the angle of forced opening of the air damper at wide open throttle of the primary chamber ("unloading angle").
A) With the primary throttle wide open, check the air damper opening angle, which is nominally (from the horizontal plane):
- version with additional damper in the secondary chamber - 50°
- version without additional damper in the secondary chamber - 45°
b) Adjust if necessary by bending the lever "unloading".
8. (Carburetor with high idle control cam position switch (FICB))
Adjust the position of the cam switch for the warm idle speed increase system.
A) Install cam (see above).
b) Apply vacuum to the FICB switch.
V) Check the mobility of the drive and make sure that the cam is in the third position.
G) Adjust if necessary by bending the FICB lever.
9. Adjust positioner ("switch") air damper (SW).
Preliminary instructions: while holding the throttle slightly open, press the choke plate and close it; while holding the choke in the closed position, release the throttle. Then, measure the choke opening angle using the procedure below.
(Auto choke carburetors (option with two diaphragms in the air damper switch actuator))
A) Install the high idle control cam (see above).
b) Apply vacuum to the internal diaphragm (A) air damper switch (SW).
V) Check the opening angle of the air damper.
- Nominal angle (first) from the horizontal plane is - 40°
G) If adjustment is necessary, remove the spring housing and bend the choke lever.
d) Apply a vacuum simultaneously to the internal (A) and outdoor (IN) diaphragm switch CB.
e) Check the opening angle of the air damper.
- Nominal angle (second): from the horizontal plane is - 55°
and) If necessary, adjust by turning the adjusting screw of the CB switch.
(Carburetor with automatic choke (option with one diaphragm in the pneumatic actuator of the air damper switch))
A) Set the cam for the warm idle speed increase system (see above).
b) Apply a vacuum to the CB switch diaphragm.
V) Check the opening angle of the air damper.
- The nominal angle from the horizontal plane is - 38°
G) If necessary, adjust by turning the adjusting screw of the CB switch in the same way as it was done for the variant of the switch with two diaphragms in its pneumatic actuator.
(carburetor with manual choke control)
With the air damper fully closed, apply a vacuum to the CB switch and check the air damper opening angle, which is nominally 38°from the horizontal.
Adjust if necessary by bending the connecting rod.
11. (carburetor option with an additional damper in the secondary chamber)
Check the additional shutter and the dispensing needle: they should move freely, without jamming and in sync.
12. Check the accelerator pump.
A) By turning the primary chamber throttle valve shaft, make sure that the pump diaphragm lever and pusher move without jamming.
13. Pre-set the opening angle of the throttle valve of the primary chamber, corresponding to the mode of normal idling.
A) (Throttle opener carburetors (TR))
Apply vacuum to the throttle opening mechanism.
b) (Auto choke carburetors) Open the throttle and then close it, leaving the choke fully open.
Attention: make sure that the warm-up idle speed booster does not turn on when doing this.
V) Check the throttle opening angle of the primary chamber.
- The nominal value of which from the horizontal plane is (approximately) for the carburetor - 13°
G) Adjust if necessary by turning the idle speed adjusting screw.
14. Pre-set the position of the mixture adjustment screw (screws "quality"), corresponding to normal idle. If the quality screw came out, fully tighten the screw and back it out about 3 turns. At the same time, do not tighten the screw with force, so as not to damage its conical surfaces.
Note: If restrictive caps are used on the quality screw, install them again.
15. Check the smooth operation of each moving part of the carburetor.