we really need a bit of help..

[albyzee]

hi, my name is carleen, and i'm posting on my husband's account because he's so frustrated right now.

we recently bought a grady '78, with an '87 mercury 150 outboard.

the merc has been running wonderfully, but when my husband opened it up the other day, there was one small part that was burned to crap. the rest of the wires and such, look just fine, but this puppy was burnt to a crisp.

it's located behind the flywheel, on top of the engine block. it has/had one red and one yellow wire attached.

can any of you identify what this part is. we've been to a few mercury 'specialists' that have steered us the wrong way.

we think it's possibly a voltage regulator..but we don't know which one.

we really would appreciate any help you can give us.

it's summer, and after 4 other boats that we've had over the years, this one finally works...we just wanna be happy.

here's what the bloody thing looks like......
(and of course you can click on the pic to make it a little bit bigger)

and thanks again.

 

[albyzee]

Re: we really need a bit of help..

(this is still carleen, albyzee's wife)

we're dying here.

i guess i should have made the title more specific, but i failed.

let me just say again that this is the first boat we've had that really seems like a good one, and we'd like to be able to enjoy this summer in it.

my husband has wanted a boat like this for years, because it starts up everytime....again, another rarity for us.

but we'd really like to know what this part is, and what it does, and where we could locate one.

i realize it's an old '87 mercury, and maybe some of you don't know about it, but we just don't know where else to turn.
believe me, we've searched on line, and also visted so many mercury 'specialists'....to no avail.

hell, our son was born in the same year, '87, and he still works well!!

 

[j_martin]

Re: we really need a bit of help..

It's a voltage regulator. It's so useless that Murkery no longer stocks it. Take it off and throw it away. You then have an unregulated 16 amp system. If you keep water in the battery, it'll be just fine.

Take the harness out, also, to prevent a short. It just goes down the right side of the engine to the rectifier mounted near the switch boxes.

hope it helps
John

 

[albyzee]

Re: we really need a bit of help..

yay!!! thank you so much john! we really do appreciate it. we have been at a loss, and it was getting so annoying. (i've had to hear my husband complaining about it for days now!)

if by chance we want to replace it, would you know what part number or identity of it, so we could get a replacement? or is it not even worth going to the trouble?


and again john, i really thank you. i'm not a newie to forums, but i'm new to this one and i appreciate your response.........carleen

 

[j_martin]

Re: we really need a bit of help..

yay!!! thank you so much john! we really do appreciate it. we have been at a loss, and it was getting so annoying. (i've had to hear my husband complaining about it for days now!)

if by chance we want to replace it, would you know what part number or identity of it, so we could get a replacement? or is it not even worth going to the trouble?


and again john, i really thank you. i'm not a newie to forums, but i'm new to this one and i appreciate your response.........carleen

It's no longer available at Mercury. All it does is clamp the output of the rectifier to about 16 volts. I suspect that you have no load, like lights etc on your battery, and maybe it's low on water or old or both, sending most of the current to the regulator. A battery in good shape is just as good a regulator. Just keep up the maintainance.

Get back on the water and burn some gas.
John

 

[albyzee]

Re: we really need a bit of help..

thanks agian, john..i really appreciate it. i'll show my husband your posts and he may get some wisdom from them...haha..i hope so.
i really thank you for your help............yay! thanks a lot.

 

[backyard mechanic]

Re: we really need a bit of help..

These guys are PARTIALLY correct. You don't need a regulator and you need an alternator either. I'm reasonably certain the battery will run the engine. How long???? Who knows. BE AWARE, the engine will not start and run forever without a charged battery.

IF by chance the engine is still charging a simple voltage check will tell you that and to what degree. There should also be a rectifier in the system to change the AC voltage from the alternator to DC. Regulators regulate voltage to your battery and they are put in the system for a reason. I'd be looking for one while you use caution in running the engine.

The problem with that is this; the more you fry the more it costs to fix it. If these wires got hot and melted what will it get up against and melt next? Remember a spark in a fuel enriched chamber (inside the engine cover) may cause fire or worse. It's been said; a fire at sea will ruin your whole day.

In summary, you need to replace the part(s) that are burned up or disconnect it all. The part you need may not be the same part as labeled in parts books for that vintage, it may well be superceeded to a new number and a part that most likely fits many outboards. A good merc parts man can identify replacement parts. You'll probably need the amperage or output of the alternator to locate a part that will work.

Good luck!

 

[j_martin]

Re: we really need a bit of help..

These guys are PARTIALLY correct. You don't need a regulator and you need an alternator either. I'm reasonably certain the battery will run the engine. How long???? Who knows. BE AWARE, the engine will not start and run forever without a charged battery.

IF by chance the engine is still charging a simple voltage check will tell you that and to what degree. There should also be a rectifier in the system to change the AC voltage from the alternator to DC. Regulators regulate voltage to your battery and they are put in the system for a reason. I'd be looking for one while you use caution in running the engine.

The problem with that is this; the more you fry the more it costs to fix it. If these wires got hot and melted what will it get up against and melt next? Remember a spark in a fuel enriched chamber (inside the engine cover) may cause fire or worse. It's been said; a fire at sea will ruin your whole day.

In summary, you need to replace the part(s) that are burned up or disconnect it all. The part you need may not be the same part as labeled in parts books for that vintage, it may well be superceeded to a new number and a part that most likely fits many outboards. A good merc parts man can identify replacement parts. You'll probably need the amperage or output of the alternator to locate a part that will work.

Good luck!

The only problem with your post is that you have no idea how this engine, or it's electrics work. Your advice is totally worthless, and in fact could be harmful, especially to the finances of these people.

This engine does not depend on the battery for anything but cranking current, and other electrical devices like the enricher solenoid, and trim motors, and a little instrumentation, none of which is necessary for the engine to run. There are 3 coil sets in the stator. 2 coil sets power the ignition system, and the other coil drives the battery charging system. The only one that is in trouble here is the battery charging system.

The stator design inherently limits the current to about 16 amps. No more is available, even if it were to be completely shorted out. The system is simply a stator providing AC electricity, a bridge rectifier converting it to DC, and a shunt regulator limiting the voltage by conducting the excess output to ground. That regulator part is what burned out.

There are many, many 13 - 18 amp systems on small engines like outboards with no regulator at all, relying on the battery to do that job.

I hate to pull rank, but there's about 40 years of personal experience in electrical engineering behind this response. If I actually shared all that I know, it would take you all night to look up the words. You won't do that, so I won't waste my time.

For Carleen and her husband,

If the rectifier goes out, and it may because they are quite weak in this engine, then the best repair would be to mount and wire in one mercury 20 amp regulator. That's a newer PWM device that is inherently cool running, and will run perfectly well in this application. You can also just replace the rectifier which takes about 5 minutes with a phillips screwdriver and a 3/8 inch wrench.

To see if the rectifier is still good, just put a voltmeter on the battery, or watch the dashboard voltmeter if there is one. It will be at 12 V or so when you start, and should go up to 14 or 15 over time as the battery charges. I suspect it is fine because it put out enough to fry the regulator.

hope it helps
John

 

[shadowcrest5]

Re: we really need a bit of help..

Hello,
I hope this helps. Go to the web site...Mercurypartsexpress.com. Once there you need to enter your serial # of the 115 hp motor. You will then be able to view exploded views of your motor...in detail. It will show the part # and prices. how-ever the pictures may be enough for you to just find the part. Good Luck......

 

[j_martin]

Re: we really need a bit of help..

Hello,
I hope this helps. Go to the web site...Mercurypartsexpress.com. Once there you need to enter your serial # of the 115 hp motor. You will then be able to view exploded views of your motor...in detail. It will show the part # and prices. how-ever the pictures may be enough for you to just find the part. Good Luck......

88825A7 This part is no longer available.

Like I said........

 

[Jeff_G]

Re: we really need a bit of help..

John I really wonder about some posters, who don't even understand how an outboard works, can contradict advise that is not only correct but easy to understand and complete.
Guys if you want top notch help don't disrespect their advise without knowing what you are talking about. And if a mistake is made own up to it. Geeez!

 

[jerbear56]

Re: we really need a bit of help..

John I really wonder about some posters, who don't even understand how an outboard works, can contradict advise that is not only correct but easy to understand and complete.
Guys if you want top notch help don't disrespect their advise without knowing what you are talking about. And if a mistake is made own up to it. Geeez!

+1 I've been following this post from a distance, and I totally agree with John. Unless these folks are running wide open for long periods, they'll most likely never notice the difference.

 

[Marty Niner]

Re: we really need a bit of help..

I would just like to jump in here if I may....does the same hold true for outboards? I have a 200 merc with two (yes 2!) fried voltage regulators. Do I need these things? If so, do I need both? I assume they are both exactly the same.

Thanks alot!