Idle Speed and Air-Fuel Mixture Adjustment

PROCEDURE

1. Remove the carburetor.
2. Secure the carburetor in a vise with soft jaw covers, so that access to the mixture adjusting screw (MAS) is possible.

3. Drill a 2 mm hole in the center of the mixture adjusting screw (MAS) hole, then enlarge the hole with a 3 mm drill bit.
4. Insert a punch into the drilled hole and drive out the plug.
5. Install the carburetor on the engine.
6. Start the engine and warm it up until the engine coolant temperature is 80–95 °C.

Adjustment Conditions

Headlights, electric radiator fan, and all electrical loads must be switched off, and the transmission must be in Neutral.

7. Drive the vehicle for 5 min at a speed of 48 km/h, or increase engine speed to 2000–3000 min⁻¹ for no more than 5 s.
8. Then let the engine idle for 2 min.
9. Adjust the CO content and idle speed by turning the idle speed adjusting screw (SAS-1) and the mixture adjusting screw (MAS).

CO content at idle speed: 2.0 ± 0.25%

Engine idle speed 1.3 L with manual transmission: 850 ± 100 min⁻¹

10. Install the plug covering access to the mixture adjusting screw.