1999 "EE" Evinrude 200, 225 V6 FFI Outboards Service Manual, P/N 787025, Page 57Get this manual
Electronic Control Unit (ECU)
The Electronic Control Unit (ECU) is located at the rear of the powerhead It has two 24-pin engine harness connectorsIt's water-cooled microprocessor that receives sensor, switch, and electrical signals that provide information on engine operating conditionsAll provide data to help the ECU control engine operating parameters such as spark advance, fuel flow, and oiling The ECU also sends electrical commands to various powerhead components to control engine operation When failure is detected, service code is storedThese inputs include: Throttle Position Shift Interrupt Air Temperature Crankshaft Position Water Temperature Oil Pressure ECU Temperature Battery 12 Volts Alternator 40 Volts Read Only Memory (ROM) Verification Barometric Pressure
The ECUbesides controlling engine operation, has number of other important programmed functionsIt: Stores service codes Activates the S.L.O.WTM Warning System Provides choke-less cold starting Outputs real-time diagnostic data Controls the System Check TM Engine Monitor gauge lights Generates tachometer signal Prevents excessive engine RPM Features 5-hour, break-in oil ratio that's twice the normal rate Controls electric fuel pump operation Records engine operating hours