1981 115 Johnson charging voltage is 16 volts

[ruddy mudder]

16-17 volts seems a bit high, how do you test the voltage regulator that sits on top of the port side of the engine? Thanks for any help.

 

[Crosbyman]

16 volts must be coming from the suspect component I doubt you could test further .
how is the battery itself ... new old sulfated ?

 

[ruddy mudder]

16 volts must be coming from the suspect component I doubt you could test further .
how is the battery itself ... new old sulfated ?

Battery is 3 years old, clean, stored inside, kept on float charger over winter. What would you consider the highest yet safest voltage for a charge rate?

 

[Crosbyman]

no expert but 14v should suffice... 16v certainly seems high and may cause some eqpt to shut down..

check battery voltage on its own...should be around 13.5 fully charged or have it load tested.

try another battery as a test see if results change

 

[Nordin]

I am not super familier with the OMCs but they should actually be similar to Chrysler/Force with in the charging system.
16 Volt is not alarming high and the regulator should start to regulate at about 16 V.
Is 16 V at WOT or at 1000-1200 RPM?
Generally the alternator start to charge at about 1000-1200 RPM and the rectifier/regulator act in at about 16 V.
The regulator is general a zener diod with zener voltage at about 15-16 V and it will ground out the alternator voltage.
If you have a good workshop manual there should be spec. for the charging system.

 

[Crosbyman]

thanks for info... may be a non issue in this case. Years ago my Merc 45 was running high causing my Humminbird fish finder to shut down. I eventually resorted to installing 3 small volt. regulators in parallel (Radio shack stuff) to give me 3 amps on the fish finder. Gave me a real nice flat 12v .

the battery survived

 

[Nordin]

I would install a separately battery for AUX devise such as fish finder and connect a voltage-sensitive differential relay.
The relay closes when the voltage reach about 13,5-14 Volt and you will not drain the starter battery for the engine by the AUX devises.