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Stator or rectifier problem?

J

Jerkalip

New member
My tach works intermittently. Whether on the flush or water, it will show rpm's, then all of a sudden go to zero. I checked (while on the flush) my battery terminals while tach was working; voltage was increasing. As soon as the tach went to zero, battery was discharging. I put the digital volt meter on the two yellow posts connecting the stator and rectifier....when tach is working, voltage was showing, as soon as the tach went to zero, there was no voltage showing at the yellows. Does this specify if the stator is not sending voltage to the rectifier, or that the rectifier is shorted out....??? What else can I do to determine which one is bad? Thank you for any professional advice. Right now I really can't afford to take it to a shop, but $50 for a rectifier won't send me to the poor house.......
 
It would help to know what engine you're speaking of.

However, for now, test the rectifier as follows... if you have this type rectifier.
(Small Rectifier Description & Location)
(J. Reeves)

On most 2,3,4,6 cylinder engines, the small rectifier is located on the starboard (right) side of the engine just in front of the engines electrical wiring strip. There are a few older V4 engines that have the wiring strip on the rear portion of the engine and the rectifier would be located just under that terminal strip. The smaller horsepower engines usually have the rectifier located on the starboard side of the powerhead close to the carburetor area.

The rectifier appears to be a round object approximately one inch (1") in diameter and also about one inch (1") high.

The base of it is sort of triangular in appearance and is attached to the engine with two (2) screws/bolts..... usually one screw/bolt is larger than the other. The rectifier, depending on which one your engine uses, will have either:

One Red wire, one Yellow wire, and one Yellow/Gray wire, or One Red wire, and two Yellow wires.
Note that either of the above rectifiers could have a fourth wire which would be Yellow/Blue
********************
(Small Rectifier Test)
(J. Reeves)

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.
 
Hi Joe, thank you very much for your information. As soon as I get a chance to try this, I'll reply. Again, thank you very, very much for your time and information.
 
Oh, Joe, I forgot to tell you...it is a 115HP Johnson, 1998 model. The model # is J115TSLECM. I also have another question for you since you seem so knowledgeable. The rectifier on is has a part number: 511938. According to what I found online, I think the correct part number is 583408. If this old rectifier proves to be okay, should I still change it because it appears to be the wrong part number??? Again, thank you.
 
The 511938 does not appear in any of the OMC or Bombardier parts price books so I can safely assume that it is not a part number but rather a factory mold or factory run number. The voltage regulator/rectifier already installed is probably the proper 583408 water cooled voltage regulator/rectifier assembly.

The instructions I inserted previously for the small rectifier does not apply as your 1998 115hp engine uses the water cooled unit. Use the following test instead.
(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).

A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging system, and the tachometer simply doesn't register.

However.... those water cooled regulator/rectifiers that are used on the 35 ampere charging systems (and some others) bring into play a different type problem, and as you've probably found out, they are really a pain to troubleshoot via the proper procedure. There's an easier way.

The tachometer sending/receiving setup operates off of the gray wire at the tachometer. That same gray wire exists at the engine wiring harness which is connected to the engine electrical terminal strip. You'll see that there is a gray wire leading from the regulator/rectifier to that terminal strip, and that there is another gray wire attached to it. That other gray wire is the wire leading to the tachometer which is the one you're looking for.

NOTE: For the later models that DO NOT incorporate a wiring terminal strip, splicing into the "Yellow Wire" mentioned will be necessary.

Remove that gray wire that leads to the tachometer. Now, find the two (2) yellow wires leading from the stator to that terminal strip. Hopefully one of them is either yellow/gray or is connected to a yellow/gray wire at the terminal strip. If so, connect the gray wire you removed previously to that yellow/gray terminal. Start the engine and check the tachometers operation, and if the tachometer operates as it should, then the regulator/rectifier is faulty and will require replacing. If the tachometer is still faulty, replace the tachometer.

If neither of the yellow wires from the stator is yellow/gray, and neither is attached to a yellow/gray wire, then attach that gray tachometer wire to either yellow stator wire, then the other yellow wire, checking the tachometer operation on both connections.

I've found this method to be a quick and efficient way of finding out which component is faulty.... the tachometer or the regulator/rectifier. It sounds drawn out but really only takes a very short time to run through. If the water cooled regulator/rectifier proves to be faulty, don't put off replacing it as they have been known to catch on fire with disastrous consequences.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
 
The rectifier I have is not the water cooled one. My understanding is that the water cooled one is on the TSX version (x-long shaft). I have the one you described earlier. It's on the starboard side, two bolts onto the side of the block. It has one yellow wire, one yellow/gray and one red. I did the ohm test you advised (First, I disconnected the positive post on my battery) .... black lead to ground against the mount, tested all three---had reading one way but not in reverse. Did the same test connecting to the red lead....as you prescribed. Again, reading in one direction but not reversed. Also, I had earlier dropped by my mechanic's shop last week. He told me to start the motor, (using DC voltage setting), place red and black leads on the block-post and take a reading on the two yellow's while watching my tach. As long as the tach was reading, I had voltage. As soon as the tach dropped to zero, the voltage went to zero. Does all of this mean that I have a stator problem instead of a rectifier problem?
 
Jerkalip said:
The rectifier I have is not the water cooled one. My understanding is that the water cooled one is on the TSX version (x-long shaft). I have the one you described earlier. It's on the starboard side, two bolts onto the side of the block. It has one yellow wire, one yellow/gray and one red. I did the ohm test you advised (First, I disconnected the positive post on my battery) .... black lead to ground against the mount, tested all three---had reading one way but not in reverse. Did the same test connecting to the red lead....as you prescribed. Again, reading in one direction but not reversed. Also, I had earlier dropped by my mechanic's shop last week. He told me to start the motor, (using DC voltage setting), place red and black leads on the block-post and take a reading on the two yellow's while watching my tach. As long as the tach was reading, I had voltage. As soon as the tach dropped to zero, the voltage went to zero. Does all of this mean that I have a stator problem instead of a rectifier problem?
Click to expand...

My reasoning for mentioning the water cooled unit was because I retired back in 1991 and I'm not familiar with the 1998 model's circuitry. Seems like your small type rectifier is okay, and I've never heard of one being intermitent.

It does sound like a stator problem. When you lose voltage, hopefully you have enough time to disconnect those two yellow wires to take an ohm reading. If you have a ohm reading initially, then lose that reading (and I suspect you do), either something is loose, a frayed broken wire, something of that nature pertaining to the stator.
 
Thank you very much for your time and input. Although I probably do not have the mechanical ability to test any further, you have set my mind to rest should the mechanic say he needs to replace the stator. One more question.... are used stators a viable option? Would that be a big no-no if the difference in cost was appealing?
 
i ran a evinrude motor with that setup from 1995 until this year....went thru about 3 rectifiers and finally one stator but the stator failure was the other winding...the ignition winding..during that time none of the rectifiers when they stopped charging was intermittent....that dont say it couldnt happen but my experience says no...you can read the output from the stator with a regular multi meter..flip to ac on the meter and start with a scale around 100volts...my manuals is at the camp so dont have exact reading with me....if you get an ac reading (i want to say in the 25-30 volt scale but not sure) then the stator is putting out...if so i would try the rectifier first because of cost difference..and even if the stator is bad i would also slap a new rectifier in it with the new stator...another option is to install the regulator at not that much more cost along with the stator...then the problem is solved forever...a new stator is around 250 bucks plus hour labor cost to install.....the basic problem is the motor charging circuit is not designed for todays batteries...a sealed battery or a gel battery is a no-no.....i have also lost a rectifier with a marine battery that you could add water as needed...if you look at your manual the recommended battery for that motor is not much more than a lawnmower battery....watch your meter and tach after you get it fixed if you keep the same non regulated setup you have now....if the meter start going into the 16-17(or higher) volt range and the tach starts reading wrong or bouncing around then you still have a problem and will eventually lose another rectifier..
 
the stator failure i had could have very well been caused by excessive heat caused by over current draw from the charging side....another tip on this motor is to make sure you keep good plugs in the motor....and the correct plugs...and you will probably never drop a power pack...pay attention to how the motor idles....the plugs can look perfect and run good at speed but new ones will make the idle smoother...i ran plugs 2 years max in that motor......
 
another way to see if the stator is putting out is to take the grey wire on the terminal block near the rectifier and move it to either of the stator output terminals....this grey wire feeds the tach...if the tach works then the stator is probably ok if the battery is not charging when you test it....
 
I am having some charging issues even after replacing the rectifier, I see that you said if the rectifier is toast the tach wont work.? Thats good info.

I test the leads off my stator to the rectifier and was get 26v AC at idle at 1500 rmp its putting out like 64v AC So I was thinking my stator is good.



joereeves said:
The 511938 does not appear in any of the OMC or Bombardier parts price books so I can safely assume that it is not a part number but rather a factory mold or factory run number. The voltage regulator/rectifier already installed is probably the proper 583408 water cooled voltage regulator/rectifier assembly.

The instructions I inserted previously for the small rectifier does not apply as your 1998 115hp engine uses the water cooled unit. Use the following test instead.
(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).

A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging system, and the tachometer simply doesn't register.

However.... those water cooled regulator/rectifiers that are used on the 35 ampere charging systems (and some others) bring into play a different type problem, and as you've probably found out, they are really a pain to troubleshoot via the proper procedure. There's an easier way.

The tachometer sending/receiving setup operates off of the gray wire at the tachometer. That same gray wire exists at the engine wiring harness which is connected to the engine electrical terminal strip. You'll see that there is a gray wire leading from the regulator/rectifier to that terminal strip, and that there is another gray wire attached to it. That other gray wire is the wire leading to the tachometer which is the one you're looking for.

NOTE: For the later models that DO NOT incorporate a wiring terminal strip, splicing into the "Yellow Wire" mentioned will be necessary.

Remove that gray wire that leads to the tachometer. Now, find the two (2) yellow wires leading from the stator to that terminal strip. Hopefully one of them is either yellow/gray or is connected to a yellow/gray wire at the terminal strip. If so, connect the gray wire you removed previously to that yellow/gray terminal. Start the engine and check the tachometers operation, and if the tachometer operates as it should, then the regulator/rectifier is faulty and will require replacing. If the tachometer is still faulty, replace the tachometer.

If neither of the yellow wires from the stator is yellow/gray, and neither is attached to a yellow/gray wire, then attach that gray tachometer wire to either yellow stator wire, then the other yellow wire, checking the tachometer operation on both connections.

I've found this method to be a quick and efficient way of finding out which component is faulty.... the tachometer or the regulator/rectifier. It sounds drawn out but really only takes a very short time to run through. If the water cooled regulator/rectifier proves to be faulty, don't put off replacing it as they have been known to catch on fire with disastrous consequences.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
Click to expand...
 
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