Carburetor fuel inlet filter (BMW 5 Series E12)

Before washing the carburetor, remove the inlet fuel filter by screwing the M3 bolt into it to a depth of about 5 mm. After washing the carburetor, install a new filter.

Checking the device for heating the air entering the carburetor

The air supply to the carburetor is regulated depending on the engine load and temperature. When the engine is cold, under the influence of the heat-sensitive element 2, the damper 1 should completely close the cold air supply channel "A" (see picture). When the engine is running or hot, the warm air supply channel "B" must be closed.

If this does not happen, the thermostat 3 with a double bimetallic spring or the heat-sensitive element 2 and its drive are faulty.

Electro-pneumatic valve for ignition timing control

The contacts of the solenoid valve are open:

• with ignition off;
• at idle speed with coolant temperature below +17°C;
• with the engine running and the throttle valve in the partial load position;
• with the ignition on and the coolant temperature above approximately +20°C;
• at idle speed when the coolant temperature is above approximately +20°C.