1999 "EE" Evinrude 70HP 4-Stroke Service Manual, P/N 787023, Page 41Get this manual
Fuel System Operation The engine uses speed-density, multi-point sequential, digital electronic fuel injection systemFuel injection control is provided by the ECUIt also operates other parts of the system, such as the high pressure fuel pump and fuel injectors, according to signals from engine sensors and switchesThese include MAP (Manifold Absolute Pressure) sensor, CKP (Crankshaft Position) sensor, CMP (Camshaft Position) sensor, Cylinder Temperature sensor, and an IAT (Intake Air Temperature) sensor
Basic Fuel Injection Duration
The basic amount of injected fuel is calculated based on two main parameters, Manifold Absolute Pressure (MAP) at the intake manifold and Engine SpeedThe ECU monitors various engine conditions and controls the length of fuel injector opening time (injection pulse width)It contains ROM (Read Only Memory) which stores the map (data) for the basic fuel injection duration at various man ifold absolute pressures and engine speeds