Yamaha F150B Service Manual

Also see for F150B: Owner's manual Service manual Owner's manual

2-8Electronic control system012345678910AFuel injection controlSimultaneous injection of group cylinders upon startingA Compression TDCSynchronousinjectionSimultaneousinjection for agroup ofcylinders atengine start-upThe fuel injection timing control applicable to the start-up modeafter the cylinder identification is completed by the pulser coil.Fuel injectors are turned on simultaneously for each cylindergroup (#1 and 4, #2 and 3), synchronized at the crankshaftangle signal reference point (BTDC 370° CA) or at BTDC 70°CA in reference to the exhaust TDC.Groupinjection innormaloperationFuel injectors are turned on in reference to the exhaust (com-pression) TDC when only the cylinder group identification iscompleted and the engine is not in the start-up mode. The fuelinjectors for a group of cylinders are turned on simultaneously.Fuel is injected two times in every two rotations of crankshaft.Asynchro-nous injec-tionAsynchronousinjection ataccelerationWhen the increment of throttle opening gets larger than the setvalue in the course of acceleration, for instance, the fuel isinjected immediately and simultaneously at all cylinders, ratherthan synchronizing with the engine rotation signal transmittedby the pulser coil. This prevents the lean air/fuel ratio, andassures the sharp throttle response in acceleration.ACylinder 1Cylinder 3Cylinder 4Cylinder 2Pulser coil signal 1Pulser coil signal 2Injection #1 and #4Injection #2 and #3Compression Combustion Exhaust Intake CompressionCompression Combustion Exhaust IntakeIntakeCompression Combustion ExhaustIntakeExhaustCombustion Exhaust Intake Compression CombustionBTDC70° BTDC10°#1 and #4BTDC70° BTDC10°#1 and #4BTDC70° BTDC10°#1 and #4BTDC70° BTDC10°#2 and #3BTDC70° BTDC10°#2 and #3