2009 Yamaha F40 Outboard Service Manual, Page 108Get this manual
Electrical system
Checking by using the digital tester
The electrical technical data apply to the measurements taken by the Yamaha recommendation testerThe resistance shown is the value taken before engine startIt may change depending on the environmental conditions and the ambient temperatureInput voltage changes depending on the battery voltageIf the tester probe cannot be inserted into the coupler, prepare test lead suitable for the measurement
Main relay input voltage: Red (R)Ground Red (R)Ground 12.0 (battery voltage) 3Turn the engine start switch to "ON," and then check the wiring harness for continuitya
Digital multimeter: YU-34899-A Test lead: Terminal, male a: (commercially available) Terminal, female b: (commercially available)