Caution! During the idle speed and CO content check, the radiator electric fan should not turn on. If the fan turns on, wait until it turns off.
Test condition: Check the exhaust system by covering the rear exhaust pipe with a rag. All pipe connections must be tight.
Caution! During this check, pay special attention to good ventilation, otherwise there is a risk of poisoning.
1. Check the play of the rods and shafts on the carburetor, repair or adjust if necessary.
2. Warm up and turn off the engine. The lower hose on the radiator should be warm.
3. Disconnect electricity consumers.
4. Check the ignition timing and adjust if necessary.
5. The air filter element must be clean. It is best to perform adjustments with a new filter element.
6. Connect the tachometer and CO measuring device according to the instructions, leave the air filter screwed on.
7. Start the warmed up engine and let it idle.
8. Check the tightness of the intake tract. To do this, apply gasoline to all connections of the intake system with a brush. If you increase the number of revolutions for a while, it means that the engine is sucking in foreign air. Identify and eliminate leaky areas.
Warning! Do not inhale fuel vapors - they are poisonous! Do not allow gasoline to come into contact with hot parts and the ignition system. Fire hazard!
9. Check the idle speed.
10. If the value does not correspond to the required one, adjust the idle speed with the adjusting screw "2".
11. Check the CO content, for required values see the end of the chapter.
12. If the CO content deviates from the required value, remove the seal from the adjustment screw. To do this, make a hole in the seal, screw in a suitable screw or self-tapping screw and remove the screw together with the seal. If necessary, remove the seal using pliers.
13. Adjust the CO content by turning the adjusting screw "1".
14. Insert a new filling.
15. Turn off the measuring instruments.
Idle speed and CO content
| Engine | CO content | Idle speed |
| E1, E3, E5 | 1,5 — 2,0% | Manual transmission: 850±50 rpm Automatic transmission: 950±50 rpm |
| VZ | 0,7 — 1,5% | |
| B5 | 1,5 — 2,0% | |
| At 6 | 0,7 — 1,5% |