Suzuki DF200/DF225/DF250 V6 4-Stroke Outboards Service Manual, Page 108Get this manual
ENGINE CONTROL SYSTEM
O2 FEEDBACK SYSTEM
After extended usage, the engine components may become deteriorated or worn outThis might make the AF (airfuel mixture ratio) incorrect which could affect exhaust emissionsTo correct the AF, an O2 sensor must be temporally installed in the exhaust manifoldThis sensor is used to measure the concentration of oxygen in the exhaust gas at engine speeds of 000, 000, and 000 rminThe ECM uses the input data from the O2 sensor to correct the compensation coefficient of the fuel injection duration map within the ECM itself