Disconnect the wire from the "–" terminal of the battery.
Remove the air filter.
1. Mark the position of the spark timing sensor relative to the auxiliary drive housing.
2. Use a screwdriver to press the spring clip on the block and disconnect the block with wires from the sensor terminal.
3. Disconnect the hose from the vacuum regulator.
4. Loosen the three nuts securing the spark timing sensor.
5. Please note: there are special washers installed under the nuts.
6. Remove the spark timing sensor.
7. Install the sensor in the reverse order of removal. Note that the projections on the sensor coupling connect to the camshaft tailstock in only one position, since the slots on the camshaft are offset from the center.
8. Before tightening the mounting nuts, rotate the sensor so that the marks made before removing it match. Check and, if necessary, adjust the ignition timing.