2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 253Get this manual
Electrical system Starter relay input voltage (reference data): Brown (Br) Ground 12 (battery voltage) 4Disconnect the battery cables, and then remove the starter relay5Connect the digital circuit tester leads to the starter relay terminalsConnect the brown (Br) lead to the positive battery terminalConnect the black (B) lead to the negative battery terminal6Check for continuity between the starter relay terminalsReplace if there is no continuity7Disconnect the brown (Br) or black (B) lead from battery terminal8Check that there is no continuity between the starter relay terminalsReplace if there is continuity
3Turn the engine start switch to "OFF 4Connect the 10-pin main harness coupler
Checking the starter relay (electric starter model)
1Disconnect the starter relay connector2Set the shift lever or remote control lever to the neutral position3Push the engine start button, and then measure the input voltage between the starter relay connector (neutral switch end) and the groundCheck the engine start button, neutral switch, wiring harness and ground lead if below specification(Tiller handle model) Turn the engine start switch to "START," and then measure the input voltage between the starter relay connector (neutral switch end) and the groundCheck the engine start switch, neutral switch (in the remote control box), wiring harness, and ground lead if below specification(Remote control model)