Tidal Fish Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
397 Posts
Discussion Starter · #1 ·
I have a 1999 Merc 200 Bluewater series with carbs, and I was wondering, what is the most volts it should charge ? When trolling it is right on 12-12.5 volts. When running, sometimes it will go as high as 15.9-16.1. Is this normal ? I run plotter, 2nd gps, vhf, sounder, and sometimes stereo. Also, I do not know RPM's as the tach has not worked since buying the boat 1 1/2 years ago. I am thinking the two may be related as I know the tach gets its feed from one of the two voltage regulators. Thanks in advance.
 

·
Registered
Joined
·
21 Posts
My 97 200hp merc charges right at 14-14.2, wether trolling or running flat out. My tac doesn't work correctly either so I don't think there is a relationship there. Chances are either you have a bad regulator, or bad cell in a batt. or else a bad guage.

You aren't using gell cell batteries are you? One thing I do know is that Mercury charging systems & gell cells don't get along
 

·
Registered
Joined
·
397 Posts
Discussion Starter · #3 ·
No I'm not using gel cells, but the boat came with new Everstart marine batteries. :eek: Maybe thats the problem. I was thinking about installing AC/Delco batteries in it though.
 

·
Registered
Joined
·
397 Posts
Discussion Starter · #4 ·
Oh yeah, gauge and sounder are both reading almost the same, but the sounder reads 1/10 volts.
 

·
Registered
Joined
·
970 Posts
I think the rectifier / regulator is one piece on that model and also drives the tach signal? It's very easy to test with the manual and a meter.

Lance
 

·
Registered
Joined
·
629 Posts
My '95 150's had two regulator/rectifiers each and the tach does run off pulses from one of them. Voltage should never go as high as 16 vdc. The original regulator/rectifiers on the 95's were not very good and could be counted on to fail, according to the tech who worked on my motors. Another possible cause of constant high output is a failed stator. The following is from a Merc service manual:

PROBLEM: CONSTANT HIGH OUTPUT
1. Remove flywheel and visually inspect stator. Discoloration
of one or more poles, or burned windings
will require replacement of stator.
2. If no visual defects of stator are found, reinstall
fly- wheel. Temporarily install ammeter (of sufficient
size to carry 50 amperes) in series with the
RED output lead (MALE bullet lead) of the regulator
and the starter solenoid.
3. Remove 1 short and 2 long YELLOW stator leads
from their bullet connectors. Run engine at
1000-2000 RPM. If no output current is observed,
disconnect 2 short YELLOW leads and 1 long
YELLOW lead. Repeat the test with the second
long YELLOW lead connected. Any output current
indicates stator is shorted to ground. Replace
stator.
4. If there is no output with either short or long YELLOW
leads disconnected, the regulators are defective.

Battery Charging System
Description
The battery charging system components are the flywheel
permanent magnets, stator, voltage regulator/
rectifier and battery. The rotating permanent magnets
induce an alternating current (AC) in the stator
coils. The AC current is rectified to direct current (DC)
by the voltage regulator/rectifier. The DC output from
the voltage regulator/rectifier is used to charge the
battery. The voltage regulator/rectifier also senses
the battery voltage as a measure of the battery’s
state of charge and thereby regulates the DC current
flow to the battery. In this manner, the battery charge
is maintained and the battery is protected from an
overcharge condition.

One of the regulator/rectifier grey leads provides the tach with pulses, the other regulator/rectifier has a grey lead, but it is not connected to anything.

Hopefully, this may provide you some help.
Jim
 

·
Registered
Joined
·
3,490 Posts
Wild One has a good description, and a good disgnostic sequence,
but most people do not have acess to the ammeter,
this may be a little simpler & without a good ammeter you can use your onboard voltmeter

1. your tach is dependent on your charging system operating properly, on most merc's the grey wire from the regulator is the tach lead

2. 16 volts is overcharging- you will "boil" (overcharging will result in low electrolite)your batteries

3.the regulator should prevent overcharging- I would replace it first
and recheck the voltage. Battery voltage should be about 13.5v with a good battery and the motor off.
start motor and raise rpm's to about 2000 and recheck voltage, it should be more than battery voltage, even with a load on it (turn on some accessories) usuaally 14-14.5

4.Inadvertently connecting a battery with the polarity reversed ,even only for a short period, will easily damage many regulators.

5.A bad stator could cause your regulator to go bad also-it is a good idea to remove the flywheel and visually inspect the stator- if there are some obvious defects (burnt,discolored etc)replace it.
but I would try the regulator replacement first (Cheapest, I think they list for $125 ea vs $425 for the stator for OEM parts)
 

·
Registered
Joined
·
660 Posts
Stator Check

There are specific resistance readings for the coils in the stator listed in the Factory service manual that will go a long way to checking the stator with an ohm meter. Removing the flywheel requires a special tool. Normal charging voltage above 1500 PRM should be 13.5 to14 volts. Both regulators (or the stator) must be bad to generate over voltage. You should probably take it to a dealer or someone that knows the troubleshooting method rather than throwing parts at it as those parts are expensive. The stator is around 400$.
 

·
Registered
Joined
·
1,247 Posts
good advice already given but I'll add my two cents anyway. Your problem is with the regulator. A simple to replace yet somewhat pricey component. 14.9 volts is is typical output. I buy most of my parts on-line from stem to stern at significant savings but you have to drop $20 I believe to be a member. From what you have said, there is zero reason to question the stator, trigger, coils or switch boxes.
 

·
Tidal Fish SUPER Subscriber - I Support Tidal Fish
Joined
·
460 Posts
First thing I would ask is what are you using to measure the voltage with. Ifi it is the gauge on the boat that is not a real accurate read. Use a good meter and measure it at idle and at WOT the voltage should read between 13.8 and 14.2 volts. It can be a bit higher or lower but not much. 16 volts is way to high and will cause battery damage.
 
1 - 10 of 10 Posts
Top