2009 Yamaha F40 Outboard Service Manual, Page 133Get this manual
Starter motorCommand Link Multifunction Meter sensor Water pressure sensor output voltage (reference data): BlueBlack (LB)Black (B) 2.5 at 392.0 kPa (3.92 kgfcm2, 56.8 psi) 4.5 at 784.0 kPa (7.84 kgfcm2, 113.7 psi) 5Turn the engine start switch to "OFF," and then disconnect the test harness and the pressure pump a6Disconnect the engine ECM coupler b Checking the speed sensor (option)
1Disconnect the speed sensor coupler a2Turn the engine start switch to "ON," and then measure the input voltage at the speed sensor coupler
Speed sensor input voltage: Orange (O)Black (B) 4.755.25 V
3Remove the speed sensor, and then connect the pressure pump and the test harness (3 pins) b4Apply positive pressure to the speed sensor slowly, and then measure the output voltage