overcharging

i have a 84 200 hp black max and i am getting 16 volts at the battery whenever i am above 1300 rpm. i have been told to replace the voltage regulator. i can't find it and i don't even know if it has one. can someone help?

Re: overcharging

Original your engine did not have a voltage regulator so you will have to purchace on ane install it. If you follow the wire that come from under the flywheel you will find the rectifier it is about 1 1/4" square and has 2 yellow wire from the stator (under the flywheel) connected to it also a gray sender wire for the tach is under one of the yellow wires and a red battery wire on the third post, it is held to the engine with 2 phillips screws. Once you have found it you will have to buy a standard regulator for a mercury and replace the rectifier with it.

Re: overcharging

i have already replaced the rectifier thinking that is the problem. if the ogiginal did not have a regulator why suddenly do i need one? if i do get the regulator, how do i install it? is this a common problem? any help is appreciated.

Re: overcharging

It's a common problem yes.
Reasons that could cause over charging-loose or corroded connections-bad or to small of a battery- sh!t happens.
For installation of a regulator get a manual or goto a web site with wiring diagrams for mercury outboards

Re: overcharging

i'm sorry but i still don't understand. why after 22 years do i suddenly need a regulator?

Re: overcharging

Like he said... you battery may not be good enough, damaged battery cables, loose or corroded connections.

Did you ever replace the stator?

Re: overcharging

i feel your pain. having the same problem with 84 50 hp merc. replaced 2 yellow wires from stator to rectifier. intalled new trigger (oem). to lake and it was charging 16-17 volts at battery. replaced rectifier again oem still over charging. tried another battery with same results. if someone can just tell me what controls voltage to battery. before all this started it charged 13-14 volts.

Re: overcharging

Resistance in the windings and wiring controls voltage output

Re: overcharging

by windings i assume you mean within the stator. (you know what happens when you assume) could not really tell what gage wire the original was so i used #14 marine grade wire when i replaced the 2 yellow wires. did i use too large of wire??? my manual does not discuss any way to check the two yellow wires.

Re: overcharging

i did replace the stator a few years ago. if i do add a regulator does it act also as a rectifier or does it go inline along with the rectifier?

Re: overcharging

bump

Re: overcharging

The mercury or CDI regulator replaces the rectifier

Re: overcharging

thank you laddies, thats what i wanted to know

Re: overcharging

you dont have a regulator, you have a rectifier.

replace it with CDI part #194-2579 and all will be good.

outboardparts.com

Re: overcharging

isn't 194-5279?? That a rect/reg., that's what you want. I think that is what Laddies was suggesting though.

Re: overcharging

iboats!! http://www.iboats.com/mall/index.cg...=944792335&list_time=1158196839&view_id=47455

Re: overcharging

wow, thats a great price! i should stock up. i paid 130.00 from my merc dealer! wow

Re: overcharging

Littlebri --

I have a 1990 150 Black Max, that just started showing the same overcharging that you experienced. Did adding the CDI 194-2579 regulator to replace your rectifier get you back into a normal charging range?

--- Mickeyd80

Re: overcharging

I have a 1988 black max. I'm amazed at how Mercury can make such an expensive motor with a sophomoric electrical system on it.

The current is limited to about 16 amps by the design of the stator. If it will put out 12 volts at idle, it will put out about 70 volts at WOT. (with no load on it) It is rectified by a cheap Mexican bridge rectifier, and dumped into the battery. The charging draw of the battery controls the voltage, depending on battery characteristics, but usually about 13.5 - 14 volts. After the battery is fully charged, the excess current just electrolyzes the water in the battery, using the water and creating lots of hydrogen and oxygen in a perfectly explosive mixture.

If you start and stop/trim the engine often, the battery never gets overcharged. If you run for awhile, and often, you will eventually fry your battery, and thus see the high voltage. If you really fry your battery, you will then fry something expensive, like ignition components, or your depth finder.

Change it out for the regulator, and all will be fine.

The "regulator" dumps the extra current into ground after full charge voltage is reached to save the battery.

The permanent magnet alternator is different than an automotive alternator in that the "field" is fully charged all the time by the magnets. In an automotive alternator the regulator adjusts the field current, and thus adjusts the output of the alternator at the source. The Mercury alternator puts out all it can all the time, limited only by the magnetic flux concentrated by the iron laminations, and engine speed.

hope it helps.

John