Melted rectifier???

Ok, so I've been trying to chase down some gremlins and ran across this. Originally trying to diagnose a dead battery situation. Got some wiring straightened out and redone. Hooked everything up and went to fire it up on the muffs with the engine cover off. Fired right up an voltage never went up just stayed 12.6. Cut it off and got to looking and and noticed a sticky residue running down. Got to looking and it looks as though the rectifier has melted. The center is soft and it seems to have bubbled up on the left side. Could this be my dead battery issue and what is the cause? Hoping your experience can help me to the right track.

1988 Evinrude xp150 v6
 

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Mr. S

New member
Chief, I have a '88 Johnson 200 GT i'm not sure it is normal but my stator looks as if it has "melted" a little as well and I have no charging issues. If i'm not mistaken the rectifier is located under the or adjacent to the power pack. I have a service manual for these engines. Here is a link to a parts explosion if that helps, you can type in your model number to see the one for your specific engine... I had a engine stutter that happened under power the engine would just shut off then come back to life all of a sudden, it turned out to be the timer base...
http://www.marineengine.com/parts/j...n&section=Ignition+System+&+Starter+Motor
 

burnett1988

New member
I had this happen to a 96 model 175 Faststrike motor, It melted down when i had it running on the ears, I thought the motor was on fire it smoked so bad, Turns out it was the rectifier regulator. Changed it out and it ran like a top.
 

silvertalon

Active member
Even if you install a known good battery, it may be too late for the regulator. With a meter hooked up to the battery, you should be reading 13.5 or better with the engine at idle speed and notice an increase as you raise rpm's.
 

chillerman69

New member
a rectifier issue would cause a no charge situation. did something cause the rectifier to fail or will is it just one of those things? have you checked the water level in your battery. if not and you can see the top of the plates, the battery could've caused the failure. I know there's probably thousands of neglected batteries that never cause issues but if I neglect anything, I get punished. I went back and re-read your cranking battery post and you never said what happened after the battery wouldn't start your motor. Jump it off and worked fine, trolled back to dock. I think the rectifier isn't cheap and be careful not to let the same battery get another one. If the rectifier and regulator are one package, the regulator could've went wild and overcharged your battery and boiled the water/electrolytes, before the no start issue. The rectifier converts AC to DC and the regulator limits the DC output to around 14.4 volts
 
Well hindsight is 20/20 as they say. To answer your question about the other day it wouldn't jump, so I trolled back to the ramp. Also the battery level is full. But after a long night of research, there have been signs, or at least one for sure. I have had intermittent problems with my tach not reading, but always seems to fix itself so I never gave it much more thought. But as always there's a learning curve and I'm beginning to learn lol.

According to my research the 35 amp rectifier/regulator can be testy and historically runs hot. It is a water cooled system. Seems the number one cause in all I've read is reversed polarity, connection mistakes. But I can assure you this hasn't been done. I'm no master mechanic but I know the risks of making that kind of mistake. The part definitely needs replacing (risk of fire) and now I'm looking into the stator. It seems there is black residue and build up on the coils which I've read is a sign that it's time for replacing. It may be working now but the end is coming.

As for the exact cause of all this I'm not sure of. Impeller was replaced and everything refreshed and looked over just over a year ago. I will say a few months back I made a long run pushing it a little harder than I normally do (only 5k rpms, usually stay around 4-42) and once I reached my destination the engine definitely seemed hot and had an electrical smell to it. Looked it over on the water and at home to find nothing substantial. Perhaps this was the begin of it's demise.

All I know is these parts are not cheap and I really want someone to have a good look at it to ensure we cover everything. Maybe it failed out of old age, it looks to be the original part, but not certain because I haven't pulled anything apart just viewed intensely.

Thank you to everyone who has responded, it is appreciated
 
Also just as I am looking at replacement parts. There's a note with all the rectifiers stating: Do not use a maintenance free, agm, or dry cell battery with this part.

Just out of curiosity, anyone know the explanation for this?
 

silvertalon

Active member
OMC stators are usually bullet proof. If you have an ohm meter and a manual, you can disconnect the boot connectors and insert pop rivets into the abcd holes and test your stator. Its actually best to use a dva meter or dva adaptor and test the cranking volts but an ohm test will work. Some darkening of the stator coils is normal as they get hot. You are looking for leaking or dripping varnish or potting. Which will indicate overheating and warrant replacement. The above needs to be tested before you install and run a new reg/rect., as, it could be damaged by a faulty stator. You are correct about battery choice. Lead Acid cranking battery always. Its not uncommon for a rectifier to overheat and melt down but it could be battery related. Get a "specific gravity tester" at autozone, walmart etc to check the individual cells. They are only a few bucks. The replacement 35 amp reg for your motor by CDI is a # 193-4205 and they run about 120 bucks.
 
Just one more real quick. I have found a parts dealer off of lake Lanier in Atlanta that has both the regulator and stator available. Both are used. Stator for $150 and regulator for $75... Would this be worth the risk of using used parts. That puts both parts for less than the cost of the regulator new.

Thanks
 

Oldman

Active member
if you have the numbers for them i will look for you.
 
Just wanted to post a few pictures of the coils.
 

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