Service manual

90-898303

3-14

FLYWHEEL

Contains two magnets which charge stator bobbins.

Flywheel has 22 teeth on outside rim which, by passing through crank position

sensor’s magnetic field, informs the ECM of engine RPM and crankshaft

angle.

CRANK POSITION SENSOR

Contains a permanent magnet and is positioned 0.040 ± 0.020 (1.02mm ±

0.51mm) from the flywheel teeth.

The timed passing of the flywheel teeth through the sensor’s magnetic field

enables the ECM to determine engine RPM and crankshaft angle.

THROTTLE POSITION SENSOR

Measures the amount of throttle opening and sends corresponding voltage

signal to ECM.

ENGINE TEMPERATURE SENSOR

Monitors powerhead temperature.

ECM uses this signal to activate fuel enrichment valve on carburetor models

and increase fuel injector pulse on EFI models for cold starts and to retard

timing in the event of an overheat condition.

Engine Temperature Sensor Graph.

NOTE: Engine timing is advanced as a function of engine coolant

temperature, which, in conjunction with fuel enrichment, aids in cold starting.

Block Temperature

C° F°

Timing Advanced By:

5 41 10°

10 50 10°

15 59 10°

20 68 10°

25 77 8°

30 86 6°

40 104 4°

50 122 2°

60 146

And Above

0°

NOTE: The amount of sensor timing advance listed above is in addition to the

normal engine timing at a given RPM. Engine timing will not advance as a

function of block temperature if crank shaft RPM is above 3000.

Notes

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