1999 "EE" Evinrude 70HP 4-Stroke Service Manual, P/N 787023, Page 53Get this manual
The Cylinder Temperature sensor is NTC (Negative Temperature Coefficient) thermistor, and has the ability to change resistance with temperatureIf temperature is high, thermistor resistance and voltage will be lowIf temperature is low, resistance and voltage will be highThe sensor detects cylinder temperature and sends voltage signal to the ECUUpon start up, the basic fuel injection duration (fuel discharge amount) and ignition timing are further modified by the ECU The ECU depends on this sensor to determine final fuel injection duration and final ignition timing during all modes of operationThis tempera ture related resistance change also serves as the signal for overheat detection IAT (Intake Air Temperature) Sensor