Re: Is my 75 hp Yamaha charging the battery ??
According to my c40 manual you measure the peak voltage coming out of the lighting coil with a peak reading voltmeter or DVA adapter and regular meter with the regulator disconnected. Should read 9V cranking and 25 V @1500RPMs . Above spec replace regulator below spec replace lighting coil
It would do you well to get a manual for your motor. It will give you all the specs for your motor and what and how to do all your repairs and maintainance