posted 11-17-2014 01:04 PM ET (US)     

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Where is the location of the voltage regulator on a Mariner 1991 60-HP 3-cylinder? At the end of the season the voltage was showing 16-volts. I suspect a failed voltage regulator. The illustrations shown for the electrical system does not show where the voltage regulator is located. Thanks in advance for help.

Pete Johnson

posted 11-17-2014 03:02 PM ET (US)            

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It's #17 on this schematic, about mid-way on the electrical plate: http://www.myfishingpictures.com/data/500/Sans_titre5.png

I had the exact same problem with a 1993 Merc 60hp (identical engine) and, beleive me, it could fry a non-sealed lead-acid battery in a few weeks, causing it to overheat and, thus, loosing electrolyte.

Different replacements available:
- Mercury #815279T @ $147
- Sierra #185743 @ $113
- CDI #1945279 @ $150

posted 11-17-2014 04:46 PM ET (US)            

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I was about to propose to sell you the service manual for that engine (serial 0D000750 & up), as I don't own that engine anymore and it's the best investment you can make, but I saw one listed on ebay for $15 OBO. That would probably cost more than that just to ship mine to you from Canada.

http://www.ebay.ca/itm/ Mercury-Mariner-Outboard-Factory-Service-Manual-50-55-60-/ 131350647332?pt=Motors_Manuals_Literature&hash=item1e951bd224&vxp=mtr

posted 11-17-2014 07:26 PM ET (US)         

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I checked out the link for the location of the regulator. My electrical plate is not the same as shown in the diagram. The diagrams I found show the voltage regulator and oil warning module just in space. I did locate the oil warning module tucked behind harness lead and electrical plate.

I though the regulator was located on the plate but no luck. I will try to trace the main red wire going to the battery and see if I can locate.

As a side note I worked for Mercury a long time ago in the stern drive engineering group but have no experience with outboards.

Pete Johnson

posted 11-17-2014 08:30 PM ET (US)         

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Saumon:

I took your advice and ordered the manual. Thanks for locating one for me!

Pete

posted 11-18-2014 03:01 PM ET (US)            

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Pete, maybe the manual will help you, but many of these smaller, older outboards don't have a voltage regulator at all - my 1989 Johnson 70 did not. They only throw about 6A and thus don't risk overcharging the battery.

On my old Johnson, once the battery finished charging back up after starting, it would show right around 16V.

Tim

posted 11-18-2014 03:50 PM ET (US)            

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Here's the diagram for the 1991 Mariner 60hp: LINK

You have to remove the black plastic panel where the fuse is in order to access the components. The voltage regulator (#39 on this schematic) is located at the very bottom of the electrical box, and kinda hard to reach.

Another possibility maybe that your engine is NOT a "newer" 1991 model because, before that, they only have a rectifier, 1991 being the year they introduce the new model with voltage regulator. We'll need your engine serial number to tell for sure but you could also look at your oil mixing system: up to 1990, it was the Auto-Blend system with remote square tank. Starting in 1991, they put the tank for the oil injection system inside the cowling.

posted 11-18-2014 07:35 PM ET (US)         

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The Model number is 7060412yd, the serial number is 0D060951. The oil tank is within the cowl. I did try to trace the wiring with no luck. I am beginning to think that this motor does not have a voltage regulator but a rectifier (item 16 in the link). Would it help to provide a photo of the area?

Pete

posted 11-19-2014 09:18 AM ET (US)            

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Yep, the newer version model start at 0D000750, so yours, with the integrated oïl tank, is definately a 1991.

A few pictures, with the black cover removed, would certainly help.

posted 11-19-2014 09:54 AM ET (US)            

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OK, I guess you're right and here's a good lesson, at least for me: instead of looking at online schematics for these engines, which all shown a voltage regulator, I physically grab the paper version of the service manual that I still have and had a look at the section covering the charging circuit: http://www.myfishingpictures.com/data/500/rectifier-regulator.jpg

It looks like somewhere early in the production run, the manual didn't mention exactly when, they add the voltage regulator because both version (with and without regulator) exist. My engine also was a 1991, serial 0D074327, and had a regulator. We can deduct from this that the voltage regulator was added on this model in 1991, somewhere between the serial number 0D060951 and 0D074327.

If you need a proof that the OEM service manual is a lot more valuable than any online schematics, that's a good one.

posted 11-19-2014 05:56 PM ET (US)         

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saumon: my electrical box looks similar to the the left page of the manual. I did get notification the manual was shipped and should be in my hands in about a week.

Pete

posted 11-21-2014 10:35 AM ET (US)         

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As far as I can determine the voltage regulator is not on this model. It was a changed sometime after the manufacture of this motor. This link shows two systems. My motor looks like the image on the left page which shows a rectifier. I'm waiting for the manual I purchased to try and verify the above statement. I did buy a replacement voltage regulator and it does not have heat fins or cooling. This link will show what the regulator looks like.

Pete

posted 11-23-2014 09:32 AM ET (US)            

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When that engine was made 25-years ago, it was likely to be connected to a flooded-cell 12-Volt battery. Such a battery is more tolerant of being charged with excessive voltage than today's more common sealed batteries with valve regulators (VRLA batteries). A vented battery will out gas when overcharged, and electrolyte will be lost, but the open design allows the lost electrolyte to be replaced (with water). More charging converts the new water into acid. In contrast, many batteries today are VRLA designs, and chronic overcharging tends to damage them. The VRLA battery will out gas, but you cannot (very easily) refill the electrolyte. The VRLA loses electrolyte over time, and becomes unable to provide electrical storage with the same capacity as when new.

With that history in mind, it is not surprising to find a 25-year-outboard engine might not have a well-regulated charging output, particularly if the outboard only has a limited charging capacity. The electrical system was probably intended to let the 12-Volt lead-acid battery act as a voltage regulator of the charging current. With only 9-Amperes of current being generated (and probably only at higher engine speeds) the unregulated charging voltage can probably be tolerated by a flooded-cell lead-acid battery without too much harm.

posted 11-25-2014 08:10 PM ET (US)         

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I received the Service Manual and the motor I have has a rectifier charging system. The rectifier is located in the lower right corner of the electrical plate. It looks like it will be a trick to replace because of the tight quarters.

Thanks to all for the feedback.

Pete