2009 Yamaha F40 Outboard Service Manual, Page 121Get this manual

Ignition units and components
Checking the thermo sensor
2Turn the engine start switch to "ON," and then measure the input voltage at the thermo sensor coupler26 34

1Disconnect the thermo sensor coupler a

Wiring harness continuity: WhiteRed (WR)Terminal 34 Black (B)Terminal 26 5Connect the engine ECM coupler and pulser coil connector a

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