Honda BF50 (5HP), BF5A Outboard Motors Shop Manual 2014, Page 39Get this manual
BF50BF5A OIL INDICATOR LAMP
Connect the BlackRed wire to the dry cell positive terminal and BlackYellow wire to the negative terminalThe indicator lamp should come on
FUSEFUSE HOLDER (Optional part)
Check the fuse for Install the fuse in the holder and check the continuity
D.CRECEPTACLE (Optional part)
After checking the fuse holder to be sure there is continuity through the fuse, short circuit the rectifier connector, and check to be sure there is continuity between the receptacle terminals