High voltage over 3500 rpms

C

Carl

Junior Member
A problem I experienced last season -

When running around 3500 rpms or higher, my garmin fishfinder (160 red) would flash a message stating the voltage was too high and within a few seconds would shut itself off. It is the only electroninc equipment I have onboard so I don't have anything else to compare it to. My volt meter would be reading around 18 volts in these situations. Is this a problem? If so, how do I diagnose and fix it. It's almost warm enough here to start working on the boat. I have a 1988 Mercury / Mariner 150.

Thanks for the help
 
No regulator, but good chance of a bad rectifier if I recall. The only parts of that charging system are the rectifier, stator, and battery.
 
We had the same problem on a 75hp Mariner.
Ended up being the voltage regulator.
192203005-1.jpg
 
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Take a picture of the powerhead so we can see what charging system you have. I believe that in 88 it could be a 9 or 16 amp system. The 9 amp was unregulated and would charge REALLY high once the batteries got charged. The 16 amp system has a regulator on it for most years.
 
I experience the high voltage also but I dont lose any electroincs. Mine goes up to 16 volts when fully charged and there is no regulator.

My question is, is it possible to install a regulator, or has anybody installed one on this type of charging system. If so what kind of results did you get.
 
I just dropped a line to CDI tech support to see what they have to say about a regulator for this type charging system. I'll let you know what they say.

Probably " turn on some lights and install a second battery" :beer:
 
same thing happened to me,, if you tach is working than your rectifier is good check your regulator,, mine was doing the same thing the faster the motor woruld run the higher the volts would get
first check the terminals on the regulator and clean them but your probably going to have to replace it
 
no exactly all true the tach will also work off the yellow/gray wire which some dealers will do so the tach works without spending the money to install a new $100 rectifer
 
BIGSHRIMPIN is the one to talk to about MERCS. Also HUMMINBIRD used to make an inline power box that would cut the voltage to your electronics to keep them below 13.8 even if your battery went to 18. But 18 is too high and you need to address that issue first. I have seen as much as 16 and sometimes 17 with no load on a 12 amp system before. Also keep a close eye on the water level in your battery at those charge levels, it doesn't take long to boil all the water out at 18 volts.

I just checked one of the big online CDI retailers and the regulator/rectifier for the 16 amp system is $145, part #194-8825K1. Make sure the grounds are good first though as without a good ground to the regulator it cannot control the charge.
 
Thanks everyone - great info. I will get a picture of the powerhead this weekend and check grounds etc.

I'll let you know how I make out and probably ask more questions too!!
 
Here is what I got from the TECH dept at CDI.

It may not answer you direct question but maybe it will give you something else to check or think about.

Turbo


Durwood,

Yes, you can install a 194-5279 regulator/rectifier to take the place of your rectifier.

But, that may not solve the root of your issue.

The #1 cause of all battery voltage issues is the battery. #2 is its connections. #3 is the regulator/rectifier. #4, the stator.

The battery and/or its connections often causes the regulator (and in some cases, the stator) to become faulty, thus often creating more than one faulty component (Example: Bad battery causing the regulator to become faulty).

1. Check all battery connections, particularly at engine ground. Make sure all connections are corrosion-free & tight.

2. If no change, remove all batteries & try a single, known-good, fully-charged off a battery charger, 850+CCA, charging (NOT a deep cycle), non-maintenance free battery (NOT a closed-case battery). Make sure the battery has vent caps on its top. Make sure to charge any battery off of a battery charger BEFORE installing. NEVER allow the stator to charge a battery. The stator is designed to keep the battery's voltage at an optimum charge. It's not designed to charge a dead or weak battery. Recheck all connections, making sure they are corrosion-free & tight. NEVER jump start a battery while an outboard engine is running. This can cause damage to the regulator/rectifier. Always use a battery charger to charge a battery. If no battery charger is available, the regulator/rectifier's red wire may be disconnected while jump starting to avoid damaging the regulator/rectifier.

3. If no change, if you have DVA equipment, DVA (peak voltage) across the stator's yellow wires at idle. Voltage should be between 17-25V DVA. If not, possible faulty stator.

4. If the stator checks good, replace the regulator/rectifier.


Please contact us again if you have any further questions.

Thank you,
CDI Tech Support
 
Alright,

I took some pics of the powerhead as noted below.

IMG_2309.jpg


IMG_2305.jpg


I have to check the grounds and connections. I ran out of time.

I found both the rectifer $27 and the regulator $148 on ebay. The voltage regultor is a discontinued part from Mercury.
 
I had time this weekend to dig into my voltage issue. I have concluded my motor does not have a voltage regulator. It has a rectifier - but no regulator. What is the right thing to do? Should I add a regulator, or another battery just to run the electronics? Or something else?

Again - any advice / direction is appreciated

Thanks
 
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