93 150 Black Max voltage regulator

Fish4fun82

Recruit
Joined
Mar 16, 2020
Messages
5
Hello I recently purchased a 93 Robolo 1820 with a 150 black max outboard. I replaceed the water pump and changed the lower unit oil. When I put it on the muffs it ran fine but after a while I noticed smoke coming from between the cylinders in the back of the motor. The box under the coils had smoke coming from the wires ( 2 red 2 yellow and a fifth wire cantrember the color) and black liquid was dripping down the back of the motor from this box. This is the top box, there is another one just below that looks identical with the same 5 wires. The wires go under the fly wheel to the stator I believe. I shut down the motor and got on this site and learned it is the voltage regulator / rectifier? I disconnected the yellow wires an put my meter on them 0 ac volts from the stator. The motor starts with the yellow wires disconnected and seams to run fine. The tach works and the battery is receiving a charge. I ordered a new voltage regulator on the internet but won’t get it for about a week. Can I run the boat with this regulator disconnected or will I damage something else.
I really appreciate any help. I’ve been using this forum for years but always found my answers without posting. Hopefully someone can let me know before I do any damage.
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
Would this not just eventually drain the battery and cut out ?
 

merc850

Commander
Joined
Jul 7, 2010
Messages
2,055
That sounds like the basic voltage at 3000 rpm, as the motor speeds up what does the voltage go to? The regulator holds the voltage @ 13.5 @ at rpms beyond 3000 - if you have a marine battery that you add water to [not maintenance free] it won't destroy it but might damage electronics. The ignition is not driven by the battery, it's only for starting.
 

Fish4fun82

Recruit
Joined
Mar 16, 2020
Messages
5
That’s what I thought as far as the battery only for starting and the motor running off the voltage provided by the stator. I’ll check the voltage at higher rpm in the am. Thanks for your help.
 

Fish4fun82

Recruit
Joined
Mar 16, 2020
Messages
5
I started the motor on muffs and increased the rpm watching the voltage gauge. The voltage gradually increased to 14 volts at 6000 rpm and stayed there dropping back down to 13.5 at 3000 rpm. I do have a new marine battery that you can add water to. So I assume as long as I keep water over the battery plates I should be ok. I wonder what the top regulator does as it appears good without it?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,562
The '93 V6 Mercs had twin 20Amp voltage regulators. They are powered by separate stator coils. You can run on a single one, if the other (bad) VR has it's wires disconnected and insulated.

Do not be surprised if the second VR fails as well. CDI makes replacements, which I have had good luck with.
 

Fish4fun82

Recruit
Joined
Mar 16, 2020
Messages
5
Thank you all for the info I’ll replace the bad voltage regulator when I receive it. I did order two. They are coming from china, I didn’t realize that when I ordered them. Hopefully they will last. Thanks again
 
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