2008 90 HP Four Stroke overcharging

[wstalker]

My charging system is putting out 17.8 volts. Is there a way without having the fancy tools to figure out if it is a stator or a regulator/rectifier? I'm new here. Thanks in advance.

[wstalker]

My charging system is putting out 17.8 volts. Is there a way without having the fancy tools to figure out if it is a stator or a regulator/rectifier? I'm new here. Thanks in advance.

I have the common tools. Multimeter, etc.

[fairdeal]

well, the stator is supposed to put out ~100 volts,

its the job of the r/r to knock that back to ~14

[zenoahphobic]

High voltage and overcharging can be two different things.
Firstly are you sure of the accuracy of the meter?
Secondly, to be sure read the voltage at the lead part of the battery terminals, to be sure that is what the battery voltage is to eliminate resistance or dirty connections.
If all is correct then you need to eliminate that the battery is still good. Is it of reasonable size?

If all is correct then your regulator is suspect. I believe it is one unit containing the rectifiers as well. You will need to have a circuit diagram for your exact motor, that someone else can tell you about.

[wstalker]

It's not just the meter. The voltage gauge, an additional digital voltage meter, and a gps all give about the same reading.

[wstalker]

well, the stator is supposed to put out ~100 volts,

its the job of the r/r to knock that back to ~14

I think that is the answer I was looking for. I will look at the regulator and maybe try a different battery. I see in my manual they show a way to test the regulator, but it is a special testing adaptor. I also have not tested at the battery.

[boscoe99]

Is the motor new to you or have you had it for a while?

If you have had it for a while, was it previously outputting nominally 14.5 volts but is now outputting 17 plus volts?

[wstalker]

I have had the boat 6 months now. Was like that when i bought it. Just didn't notice at the time

[RetiredGuy]

Not sure if your 2008 is the same as my 2010 90Hp
Replaced my R/R under warranty - it was putting out 16 plus volts - too high for me - New one still high at 15Vdc
The replacement came with a short pig tail while the original had the socket embedded in the plastic part
Guess the pigtail was needed to help keep warranty costs down when the R/R's burn up and take the wiring harness along with them
IMO not a very good design and weak point with the Yamaha's

[boscoe99]

Yamaha does not provide any maximum voltage specification.

Given the relatively low electrical output of an F90 motor 16/17 volts is probably not hurting anything. Might set some alarms on overly sensitive electrical components however.

Turning on some lights or adding some electrical loads should help to bring the voltage down for anyone that is concerned.

[walleye1]

I found on Mercury engines [opti verod] they will throw a code at 14.7 volts. [Alternator] 16 volts will burn up a battery.

[boscoe99]

An alternator might but I doubt a low amperage PMG will.

Found this in an F90C service manual. Strange as it may be.

[CatCam]

My 2004 F90's output is between 14.4V - 14.6V

[boscoe99]

My 2004 F90's output is between 14.4V - 14.6V

Meets the minimum specifications. Good.