1. Connect the stroboscope to the spark plug wire of the first cylinder (follow the instrument manufacturer's instructions).
2. Disconnect wiring from auxiliary air valve (AAS), located at the rear of the pressure chamber of the air path (see accompanying illustration).
1 - additional air valve (AAC)
2 — the screw of adjustment of turns of idling
3. Start the engine and warm it up to normal operating temperature. Raise the engine speed two or three times to 2000 ÷ 3000 per minute, then reset it again to idle.
4. With the engine running at idle, illuminate the distribution mark on the crankshaft pulley with a stroboscope and make sure that it is aligned with the 10°mark on the scale on the timing cover.
5. if necessary, correct the ignition timing by loosening the fixing bolt and turning the distributor housing accordingly.
6. Upon completion of the adjustment, tighten the distributor mounting bolt.
7. Make sure the engine idle speed is maintained at 600±50 rpm. If necessary, correct them by turning the adjusting screw.
8. Stop the engine and connect the electrical wiring to the AAC valve.