2009 Yamaha F40 Outboard Service Manual, Page 123Get this manual
Ignition units and componentsStarting units and components 9Install the neutral switch, and then connect the neutral switch coupler a Checking the engine shut-off switch
1Disconnect the 10-pin or the engine start switch coupler2Turn the engine start switch to "ON," and then check the engine shut-off switch for continuityOFF ON START
Starter relay input voltage: Brown (Br)Ground 12.0 (battery voltage) 3Turn the engine start switch to "OFF 4Disconnect the starter relay leads, and then remove the starter relayNOTICE: Always disconnect the negative battery terminal before disconnecting the starter relay terminals5Connect the positive battery lead to the relay connector a, and the negative battery lead to the relay lead b, and then check for continuity between terminals and dReplace the starter relay if out of specification