Charging system advise

[BullGang]

I am running a 1988 Vpro 200hp on my 21.5 center console. My voltage meter will only go to about 12 volts after getting 1500rpms or more. *****ing it will only go above 10volts and my batteries are dieing out half way through the day. I need a wireing diagram for the charging system would anyone have it as a pic or know where I can get it. Need to figure out if I have a short drawing against my charging system or if its just gone bad and need to replace voltage regulator.

[99yam40]

The Yamaha service manual for your motor will have procedures to test lighting coil and rectifier/regulator along with the specs, and will have wiring diagrams