2009 Yamaha F40 Outboard Service Manual, Page 40Get this manual
TECH FEA Pulser coil
Technical features and description
A single pulser coil determines the engine revolutions, the crankshaft angle, and the direction of the crankshaft rotationThe pulser coil also detects the changes in pulse using the convexo-concave shape in the outer edge of the flywheel magnetThe engine ECM figures out the crankshaft angle based on the pulse signal changesPulser coil
Convexo-concave shape
Signals from the pulser coil and the ignition and injecting timing are as followsInjection and ignition orders are 132, but combustion order is 123The engine ECM determines that the crankshaft angle isis #3 TDC The engine ECM determines that the crankshaft angle #3 TDC because there is nono pulse signalbecause there is pulse signal