Yamaha F100B F100C Outboards Factory Service Manual, Page 15Get this manual
Features and benefits Hour meter newly developed hour meter is incorporated on the F100B and F100CThe hour meter makes it possible to check the hours of operation of the outboard motor, which can be used to keep track of periodic checks and adjustmentsWhen the engine switch is turned to ON, all LED on the display will illuminate for two seconds, and then the hours of operation will be displayedA signal from the Rectifier Regulator, via the green and white (GW) lead, is sent to the hour meter as the hours of operation accumulationThe hours of operation cannot be deleted