1996-2005 Suzuki DF40, DF50 Four Stroke Outboard Service Manual, Page 73Get this manual
ENGINE CONTROL SYSTEM 3-18
FUEL PUMP CONTROL SYSTEM
OUTLINE To supply the optimum fuel amount, the ECM controls the fuel pump drive duty cycle, repeated ON OFF signal, at specified rate (1000 times second)Based on engine speed and battery voltage, the ECM determines the optimum duty (repeating "ON" time rate within cycle) and sends this signal to the fuel pumpCKP sensorInforms ECM of engine speedBattery voltageIgnition switchInforms ECM of "START" signalECM Signal FP Fuel pump
Battery charge coil Rectifierregulator 30A fuse ECM main relay
Duty cycle signal for fuel pump (example80 duty) "ON" time 100duty () cycle time 0.8 ms OFF