What can short out a Stator?

mike8809

Cadet
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Aug 9, 2008
Messages
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Have a 1998 Mercury 200 offshore. Had no spark on all cylinders. Replaced stator and ran 5 minutes then blew the stator. What could blow the stator? Trigger checks out but I don't know how to check the switch boxes. Would that even blow the stator? Batteries are holding charge.
 

Laddies

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Sep 10, 2004
Messages
12,218
Re: What can short out a Stator?

Check the rectifier/regulator. Disconnect the kill curcut wire(black/yellow) from the box to see if it's shorted. Don't use Mercury ign. parts.
 

mike8809

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Aug 9, 2008
Messages
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Re: What can short out a Stator?

Hi. Thanks for your prompt reply. I don't have a tethered kill switch. Do you know how to check the rectifier/regulator on bench without power? I don't want to put another stator in and have it blow again.
 

Laddies

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Re: What can short out a Stator?

Have you the number off the rectier/regulator ao I sentd the right one.
 

Laddies

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Re: What can short out a Stator?

scan0002-1.jpg
 

mike8809

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Aug 9, 2008
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Re: What can short out a Stator?

Thanks again for your help. I did tests and got following readings:

First Diode Check - no reading and the tachometer - no reading. Everything else checked out.

So could that short the stator? What about the switch boxes? Switch box numbers: 332-7778A13 and 068 0768.

Thanks, Mike
 

Laddies

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12,218
Re: What can short out a Stator?

Something is building heat in the system, check the ground wire from the stator, I hope that you are using CDI parts as Mercury electronics are not worth the time it takes to install them. I am not a V6 person and not that familiar with them. The best place to find a anwser is goto the CDI/Rapair site or call their tech. support.
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
Messages
19,428
Re: What can short out a Stator?

Bad battery trying to draw too much current.
The stator windings supply power to the pacs (winding A)and supply power for the charging system(winding B)
 

j_martin

Admiral
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Sep 22, 2006
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7,474
Re: What can short out a Stator?

Last time I heard of this problem it turned out that 16 amp stators were being put under a 40 amp flywheel. They ran about 5 minutes.

hope it helps
John
 

mike8809

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Aug 9, 2008
Messages
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Re: What can short out a Stator?

thank for the responce how do you tell them apart? the two I have (old & new) look the same.

thanks Mike
 

j_martin

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Sep 22, 2006
Messages
7,474
Re: What can short out a Stator?

What killed the old stator? How long did it live?

A 40 amp flywheel looks quite a bit different than a 16 amp, but it will go over a 16 amp stator. I've seen it done, and that's what usually happens.

A bad top bearing, allowing the flywheel to touch the stator will also quickly overheat the stator and burn it out. Goes without saying that a stator getting loose on the mounting would do the same thing.

If you don't know what you got, take pictures and post them.

hope it helps
John
 

mike8809

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Aug 9, 2008
Messages
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Re: What can short out a Stator?

Hi John. I had the boat about 4 years and had the same stator on it and one day it just quit. I replaced with the second stator and it only worked for about 5 minutes.

Prior to the first stator blowing, engine had to crank longer than normal. Did stall a couple times but did restart. Boat slow to come up to speed but eventually did come up to speed. This all happened in the same day. Then when it finally died, it never restarted. I replaced stator, fired up immediately and ran great for 5 minutes. I did not check the rectifiers when I replaced the stator.

My rectifiers don't check out properly. Would this be the cause of the stator problem? Did the rectifiers perhaps short the stator out? Or could it be something else? Top crank bearing is tight, fly wheel is tight, not sure if it was a 16 amp stator (checking with place I bought it from) but the stator visually looks like the same as the one that it replaced. Could I just have gotten a bad stator?

Thanks again for your help.
Mike
 

j_martin

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Sep 22, 2006
Messages
7,474
Re: What can short out a Stator?

Hi John. I had the boat about 4 years and had the same stator on it and one day it just quit. I replaced with the second stator and it only worked for about 5 minutes.

Prior to the first stator blowing, engine had to crank longer than normal. Did stall a couple times but did restart. Boat slow to come up to speed but eventually did come up to speed. This all happened in the same day. Then when it finally died, it never restarted. I replaced stator, fired up immediately and ran great for 5 minutes. I did not check the rectifiers when I replaced the stator.

My rectifiers don't check out properly. Would this be the cause of the stator problem? Did the rectifiers perhaps short the stator out? Or could it be something else? Top crank bearing is tight, fly wheel is tight, not sure if it was a 16 amp stator (checking with place I bought it from) but the stator visually looks like the same as the one that it replaced. Could I just have gotten a bad stator?

Thanks again for your help.
Mike


The 16 amp and 40 amp stators are considerably different in appearance. The laminations are about an eighth inch thicker on the 40, and all 12 poles are exposed, instead of a few of them being encased as is the 16.

A shorted rectifier shouldn't hurt the stator, at least quickly. It could be a factor that along with say, massive engine overheat, could contribute to failure.

If it's the right one, and if the flywheel isn't hitting it, you got a bad new one.
You say rectifiers. (plural) There should be one rectifier module hooked up to a 16 amp stator. Maybe a regulator module hooked up to the rectifier module.

If in doubt, pictures would help.

hope it helps
John
 
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