Still fixing this '94 Merc 150hp 2.0V6

ClassyGlassy · May 14, 2010

Hey guys, I got it running today and after about 45 seconds I shut it down......here's why:

1. No water coming out of the "pee" hole

2. Light smoke starting coming from around the coils, behind the coils and against the exhaust plate are two boxes between the plate the coils are mounted on and the exhaust plate itself. They both have 2 Red wires, 2 Yellow wires, and 1 Grey wire. The top one's Grey wire is connected to the harness that the other wires go into while the bottom one's Grey wire is plugged off. The bottom one was shooting a reddish orange flame and smoking badly.

I have removed both boxes to find the top one has some damage where the gel has started to crack from getting hot probably from the initial damage from before. I'm assuming that that one will still work O.K. But you can see the damage of the lower one that was burning and that it needs to be replaced. Numbers on the boxes are 815279-3 and 2694.

Any and all help with identifying these boxes and if I have to get used ones to keep prices down would be much appreciated.

Thanks

CDI Tech Support · May 14, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

ClassyGlassy said:
I have removed both boxes to find the top one has some damage where the gel has started to crack from getting hot probably from the initial damage from before. I'm assuming that that one will still work O.K. But you can see the damage of the lower one that was burning and that it needs to be replaced. Numbers on the boxes are 815279-3 and 2694.

Any and all help with identifying these boxes and if I have to get used ones to keep prices down would be much appreciated.

Thanks

Definitely would replace both regulator/rectifiers. Anytime one blows, it's always a good idea to replace both at the same time. The fact that the top one has some damage and has cracked the potting encapsulation only confirms replacing both.

Our replacement part# is 194-5279. List price is $158.00 each. We sell direct. They can also be purchased through iboats.

Also give the stator a good visual check. If there are any signs of browning, overheating or varnish dripping, replace the stator too.

Also, most regulator failures are attributed to improper battery type and/or battery charging neglect. Read this article to determine if you need to replace your battery, what battery types are recommended & how to maintain the life of your battery, regulators & stator:

Battery Charging Issues, Regulator-Rectifiers and Tachometers

ClassyGlassy · May 14, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

thanks for the information.........

This damage was originally caused by an overheated motor that melted the wires on top of the powerhead and caused a bunch of smoke before it was shut down. Then sat for 2 years before my dad finally brought it over to me.

ClassyGlassy · May 14, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

I just purchased a used one from Doug Russell.com for $72!

Does anyone have a wiring diagram that will tell me whether or not both Grey wires are supposed to connect to something or if one is supposed to be capped off?

Thank you.......

j_martin · May 14, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

ClassyGlassy said:
I just purchased a used one from Doug Russell.com for $72!

Does anyone have a wiring diagram that will tell me whether or not both Grey wires are supposed to connect to something or if one is supposed to be capped off?

Thank you.......

The grey wire is the tach connection. Only one is needed. Either one will do.

Those are the original 20 amp regulators, and they are noted for being weak. If the potting is discolored, it is most likely bad. The newer replacement ones (usually black potted, with a ground wire) are stronger.

Like you were told, if the stator is discolored or plastic on it melting, replace it.

Yes, gross overheat would likely stress these parts, especially if they are charging a defective or dead battery at the same time.

hope it helps
John

ClassyGlassy · May 14, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

Thanks J,

I figured the grey one was for tach and now you've confirmed it. As for the other one, the Yellow potting is still bright yellow and clear. It just has a crack pot....

Just kidding........ it has a small crack in it and I'm not worried about it having an issue. My dad knows that replacing both of them is going to cost about $300 and plans on doing so at the end of the summer. The used one I have coming will suffice for the couple of times he uses his boat each year.

I went ahead and checked the stator wires and traced everything up to the flywheel. Nothing looks overheated. There is NO evidence of a problem anywhere! I would like to know, however, if there is a resistance test to check the performance of the regulators so I know if the used one coming works or not as well as testing this other one with the small crack in the potting.

Thanks

ClassyGlassy · May 14, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

I found it thanks to CDI...

Regulator/Rectifier Bench Tests
1. Diode plate check:
With all wires disconnected from the regulator/rectifier, using a meter set on its Diode scale, test the diodes
from each of the two battery charge wires/terminals (typically Yellow wires/terminals) to the Red wire/terminal.
You should get a reading one way but not the other. Check the resistance from each of the Yellow
wires/terminals to case ground. You should have a high reading, typically in the M range. The Red
wire/terminal should not read to ground, but may show a very high reading (25M ohms or more).
2. Tachometer Circuit:
With all wires disconnected from the regulator/rectifier, check resistance between the Gray wire and engine
ground. You should read approximately 10K (10,000) ohms. Both (Gray to Red) and (Gray to each of the
Yellow) wires should be a high reading, typically in the M range.

Chris1956 · May 15, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

Classy, A lot of those V6 motors have the telltale downstream of the thermostats. You get no flow until the motor warms up. If you run it on a hose, you will see the motor sucking the water in, and you will know the pump is working. A lot of times on the hose the 'stats never open.

CharlieB · May 15, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

IF the motor has been sitting for a couple of years with an OLD impeller in it, then it would be a GOOD MAINTENANCE measure to go ahead and replace the impeller, just to stay on the safe side.

ClassyGlassy · May 15, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

CharlieB said:
IF the motor has been sitting for a couple of years with an OLD impeller in it, then it would be a GOOD MAINTENANCE measure to go ahead and replace the impeller, just to stay on the safe side.

Thanks Charlie,

Impeller was changed along with both thermostats just not by me so I was nervous about not seing anything from the telltale after the 45 seconds I ran it........I don't think it was anywhere near warm enough for the stats to open. I live at 8000 feet and the ground water is cold!

j_martin · May 15, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

ClassyGlassy said:
Thanks J,

I figured the grey one was for tach and now you've confirmed it. As for the other one, the Yellow potting is still bright yellow and clear. It just has a crack pot.... Just kidding........ it has a small crack in it and I'm not worried about it having an issue. My dad knows that replacing both of them is going to cost about $300 and plans on doing so at the end of the summer. The used one I have coming will suffice for the couple of times he uses his boat each year.

I went ahead and checked the stator wires and traced everything up to the flywheel. Nothing looks overheated. There is NO evidence of a problem anywhere! I would like to know, however, if there is a resistance test to check the performance of the regulators so I know if the used one coming works or not as well as testing this other one with the small crack in the potting.

Thanks

The easiest way is to disconnect the yellow wires from one and see if the other one will charge the battery. Then try the other one.

It's basically 2 completely independent 20 amp charging circuits.

hope it helps
John

ClassyGlassy · May 15, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

so 2 individual 20amp charging systems causes it to be a 40amp circuit? I keep seing that it's a 40amp system..........

CDI Tech Support · May 17, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

ClassyGlassy said:
As for the other one, the Yellow potting is still bright yellow and clear. It just has a crack pot.... Just kidding........ it has a small crack in it and I'm not worried about it having an issue. My dad knows that replacing both of them is going to cost about $300 and plans on doing so at the end of the summer. The used one I have coming will suffice for the couple of times he uses his boat each year.

Potting encapsulation is used on outboard parts for a very good reason -> water. Even condensation can short out the regulator's circuit. And if it shorts out, it can possibly take out the new regulator you're about to install as well as the stator.

If you cannot afford to replace the regulator at this time, I would, at bottoms, seal the crack with RTV silicone. Keep in mind this isn't a suggestion. It's merely a band-aid. Condensation can still seep between silicone & the potting encapsulation, especially once the engine heats up & those things called expansion & contraction take over. Gotta love the laws of Physics!

j_martin · May 17, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

ClassyGlassy said:
so 2 individual 20amp charging systems causes it to be a 40amp circuit? I keep seing that it's a 40amp system..........

Yep, that's the way it is. Neat thing is you can divide the task and have one charge your main battery, and one charge the backup/trolling battery. The other neat thing is that if one fries, the other one will usually carry the day.

The other 40 amp Mercury system they had for a few years used one stator coil and one big water cooled regulator mounted right over the exhaust chest. Didn't take much of an air bubble to immediately fry it. Most cost effective fix is to convert it to a dual regulator 40 amp like you have.

ClassyGlassy · May 17, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

j_martin said:
Yep, that's the way it is. Neat thing is you can divide the task and have one charge your main battery, and one charge the backup/trolling battery. The other neat thing is that if one fries, the other one will usually carry the day.

The other 40 amp Mercury system they had for a few years used one stator coil and one big water cooled regulator mounted right over the exhaust chest. Didn't take much of an air bubble to immediately fry it. Most cost effective fix is to convert it to a dual regulator 40 amp like you have.

For future reference, and until he can afford to buy 2 new ones, how do we tape off the wires going to the second one that fried? I still need to test the work that I did on this motor and the fact that he only has 1 battery, no toys attached, he should be able to do a little fishing using just the one. So do I just tape off the ends and start it?

ClassyGlassy · May 17, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

CDI Tech Support said:
Potting encapsulation is used on outboard parts for a very good reason -> water. Even condensation can short out the regulator's circuit. And if it shorts out, it can possibly take out the new regulator you're about to install as well as the stator.

If you cannot afford to replace the regulator at this time, I would, at bottoms, seal the crack with RTV silicone. Keep in mind this isn't a suggestion. It's merely a band-aid. Condensation can still seep between silicone & the potting encapsulation, especially once the engine heats up & those things called expansion & contraction take over. Gotta love the laws of Physics!

Thanks for the information and honesty CDI, too often companies want to just tell you replace, replace, and replace.....they don't tell you to seal it for temporary use until you can afford to replace! $200-$300 to replace 2 regulators can be suffocating when you're not ready for it......we own older boats because we can't afford new ones.

I ended up not being able to find a used one either......DougRussell.com won't sell used anymore. So in a time where the economy takes a dive, you can't find parts you can afford because no one will sell you a used one. I've spent 4 days now looking for someone who will sell me a used one. He just wants to use the boat for a couple of months this summer and then he'll get new ones for next year.........such a shame to not be able to do this.......

j_martin · May 17, 2010

Re: Still fixing this '94 Merc 150hp 2.0V6

ClassyGlassy said:
For future reference, and until he can afford to buy 2 new ones, how do we tape off the wires going to the second one that fried? I still need to test the work that I did on this motor and the fact that he only has 1 battery, no toys attached, he should be able to do a little fishing using just the one. So do I just tape off the ends and start it?

Yep, tape the wires off on the bad one, and if the battery then charges, go fishing. If there's a grey wire connected to the bad one, that's for the tachometer. Move it to the other one.

BTW, loose yellow stator wires can develop 90 VAC, and bite like a crocodile or even put you under. Do it right.

Still fixing this '94 Merc 150hp 2.0V6

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