92 90hp yam overcharging

[no excuses]

my 1992 90hp yam will slowly overcharge the battery when running for extended periods. The volts will slowly climb up into the high 14's and low 15's Volts and give me a high voltage warning on my vhf radio. If I turn on my Nav. Lights the volts drop down enough (14's) that the warning goes away. I am guessing that i am having voltage regulator issues. How to test and where are they located? Thanks for any help, stan..

[outboardtech]

Ok stan , i have come across this problem a few times out in the field . This problem does not NECESSARY mean its the rectifier/reg on the engine ok . Firstly how many items have you got running off your main cranking battery ? You should always run your outboard on its own battery , i know you r thinking NO WAYS alot of people I know have all sorts of things connected to the one battery but this is were you start too have problems . All you need is for your VHF radio to have a bad earth and it upsets the whole system . What i would do if I were u was connect a battery directly too the outboard with a set of battery cables ( NOT TOO CROCODILE CLIPS ) to good set of battery cables and run your outboard and put a volmetre across the post and see what its reading . Run it @ idle and take a reading then run it @ 3500 and take a reading . Lets start here first ok . baz

[no excuses]

Baz I only run one battery so I am running my gps/depth finder, VHF radio and running lights off of it. I will try disconecting everything but the motor and check the volts as suggested, will have to wait till this weekend to try this. Stan