1999 "EE" Evinrude 70HP 4-Stroke Service Manual, P/N 787023, Page 45Get this manual
The ECU controls injector operation by opening and closing individual injector ground circuitsIn doing sothe ECU can change both the timing and duration of the fuel charge (pulse width)The ECU adjusts injector operation in respect to data received from various powerhead sensorsThe ECU cannot, however, detect an injectorcircuit failure, so it will not store service code Cylinder Head The cylinder head at the rear of the powerhead mounts one fuel injector and one spark plug per cylinder Their positioning is designed to permit complete combustion and maximum power from each airfuel chargeThis results in greatly reduced exhaust emissions and increased fuel economy Cooling System Operation