Screws for adjusting the mixture quality and idle speed
1 – mixture quality adjustment screw,
2 – idle speed adjustment screw
To adjust idle speed and mixture quality, you need a tachometer and an exhaust gas analyzer.
1. Warm up the engine to operating temperature.
2. Turn off all electrical consumers.
3. To access the mixture quality adjustment screw, remove the air filter housing, ensuring a secure connection between the vacuum tube and the cylinder head cover hose.
4. Disconnect the radiator fan temperature sensor connector and short-circuit both contacts with a jumper to enable the fan to operate continuously.
5. Check the initial ignition timing setting.
6. Connect a tachometer (with the ignition off) and a gas analyzer to the engine.
7. Increase engine speed to 3000 rpm and hold it for 30 seconds, then return the engine to idle.
8. Take instrument readings.
9. If the idle speed deviates from the norm, use the mixture quantity adjustment screw to set the required speed.
10. If the CO content value deviates, remove the protective cap from the mixture quality screw, increase the engine speed to 3000 rpm and hold it for 30 seconds, then switch the engine to idle mode and, by turning the mixture quality screw, set the required CO level.
11. When changing the idle speed, adjust it with the mixture quantity adjustment screw.
Attention! Readings of the instruments and adjustments can be made only after the readings of the measuring instruments have stabilized.
12. In the absence of a gas analyzer, approximate adjustment of the mixture quality can be made as follows. With the engine running, turn the mixture quality screw inward until the idle speed begins to noticeably decrease, then slightly unscrew the screw in the opposite direction until smooth engine operation is achieved.
Information for this article was taken from the website Fordbook.ru