1996-2005 Suzuki DF40, DF50 Four Stroke Outboard Service Manual, Page 87Get this manual
ENGINE CONTROL SYSTEM 3-32
O2 FEEDBACK SYSTEM
After extended usage, the engine components may become deteriorated or worn outThis might make the(airfuel mixture ratio) incorrect which could affect exhaust emissionsTo correct the AF, an O2 sensor is temporally installed to the exhaust manifoldThis sensor is used to measure the concentration of oxygen in the exhaust gas at engine speeds of 2500, 3500 and 4500 r minThe ECM uses the input data from the O2 sensor to correct the compensation coefficient of the fuel injection duration map within the ECM itself