2. Check carburetor and drive.
A) Check the presence and position of the adjusting screws, plugs and bolts.
b) Check the condition and wear of the drive parts, the presence of latches, etc.
V) Check the full throttle opening when the accelerator pedal is fully depressed.
3. Check the fuel level in the float chamber against the marks on the sight glass. If the fuel level is out of specification, adjust.
Cold engine
4. Check the automatic choke control system.
A) Start the engine.
b) Make sure that the air damper begins to open as the heater body warms up.
V) Stop the engine.
G) Disconnect the carburetor electrical connector.
d) Using an ohmmeter, measure the resistance between the carburetor connector terminal and "weight", the value of which at an air temperature of 20°C is:
For engines:
- 2Y-C (U) and 3Y-C (U) — 23-25 Ohm
- for the rest of the Y series - 17-19 Ohm
5. Check choke position switch system (CB system).
(Variant with automatic choke and double diaphragm in switch actuator)
A) Start the engine.
b) If the coolant temperature is below 5°C, disconnect the vacuum hose from diaphragm B and check that the damper does not move.
V) Connect vacuum hose to diaphragm B.
G) Disconnect the vacuum hose from switch diaphragm A and check that the choke plate moves.
d) Connect the vacuum hose to diaphragm A and check that after connecting the hose, the damper moves within the set time (1-5 s).
(Option with automatic air damper with a single diaphragm in the pneumatic actuator)
A) Start the engine.
b) Disconnect the vacuum hose from the choke switch (SW) and check that the choke mechanism moves.
V) Connect the vacuum hose to the switch diaphragm mechanism (SW) and make sure the choke plate moves within the set time (1-5 s).
(Variant with manual air damper and single diaphragm in switch actuator)
A) Start the engine.
b) Disconnect the vacuum hose from the choke switch diaphragm mechanism (SW) and check that the choke mechanism moves.
V) Reinstall the vacuum hose.
6. (With an automatic air damper control system (CO systems) and cam control mechanism increased idle speed (FICB))
Check the high idle control cam switch (FICB).
A) Disconnect the vacuum hose from the cam drive diaphragm mechanism (FICB).
b) When the coolant temperature is below 55°C°C, press and release the accelerator pedal.
V) Start the engine.
G) Connect the vacuum hose and check that the choke actuator does not move.
7. (With an additional accelerator pump system (AAR))
Check Auxiliary Accelerator Pump System (AAR).
A) Make sure the coolant temperature is below 55°C and start the engine.
b) Pinch the AAP hose and stop the engine.
V) Loosen the hose and check that fuel is being injected from the AAP injector.
8. (With float chamber unbalance valve (OVCV carburetor ventilation systems)) Check operation of unbalance system valve (ventilation systems) float chamber.
A) Disconnect the ventilation hose from the carburetor.
b) Blow air into the vent tube and make sure the OVCV valve is open.
V) Start the engine. With the engine idling, apply air to the vent tube and make sure the OVCV valve is closed.
G) Disconnect the electrical connector from the carburetor.
d) Using an ohmmeter, measure the resistance between the OVCV terminal on the connector and "weight''.
- Resistance value (cold engine): 63 - 73 ohm.
e) Reconnect the ventilation hose.
Warm engine
9. (Variant with double diaphragm automatic choke in pneumatically actuated choke position switch)
Check the function of the positioner system ("switch") damper position (SW).
A) After the engine is warm, disconnect the vacuum hose from diaphragm B and check that the throttle plate moves.
b) Connect vacuum hose to diaphragm B.
10. (With an automatic air damper control system (CO systems) and cam control mechanism increased idle speed (FICB))
Check the high idle control cam switch (FICB).
A) Warm up the engine to normal operating temperature and stop it.
b) Disconnect the vacuum hose from the air damper diaphragm mechanism (and cam FICB).
V) Install the high idle cam (FICB). To do this, hold the throttle slightly open (1), close the choke (2) and hold it closed as you release the throttle (3).
G) Start the engine without touching the accelerator pedal.
d) Connect the vacuum hose and check that the choke actuator moves and the FICB cam moves to position 3.
11. (Automatic choke option)
Check the full opening of the choke by making sure that the choke plate opens fully.
12. (With an additional accelerator pump system (AAR))
Check Auxiliary Accelerator Pump System (AAR).
A) Warm up the engine to normal operating temperature.
b) With the engine running, pinch the AAP hose, then stop the engine.
V) Loosen the AAP hose and check that no fuel is being injected from the AAP nozzle.
13. (With an additional accelerator pump system (AAR))
Check Auxiliary Accelerator Pump Diaphragm (AAR).
A) Start the engine. With the engine running, disconnect the hose from the AAP diaphragm mechanism.
b) With the engine idling, apply a vacuum directly to the AAP diaphragm, and then remove the vacuum.
V) Make sure the engine speed changes when the vacuum is removed.
G) Reconnect the hose to the AAP diaphragm mechanism.
If a malfunction occurs, replace the AAP diaphragm.
14. Check the accelerator pump (basic).
Open the throttle and check that fuel is being injected through the injector.
15 Install the air filter or air line to the carburetor.
16*. Check the increased idle speed when the engine warms up.
17*. Check normal idle speed and mixture.
18*. Check the speed set by the throttle opening mechanism.
19*. Check the speed set by the manipulator (positioner) throttle valve.
20*. Check the increase in idle speed, set by the amplifier in the control system.
* See pages 8-10.