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Author Topic:   Erratic charging voltage underway
bear99 posted 01-08-2008 09:41 PM ET (US)   Profile for bear99   Send Email to bear99  
Gentlemen, My 1986 Revenge 22 W-T with Mercury 200 carburetor two-cycle motor (S/N OG111433) is experiencing fluctuations in voltage. After approximately 30 minutes of use above idle the voltage will rise from 14.5 to 17. This will cause the depth sounder to shut down and VHF to switch from scan to a single channel which is the weather channel. I pull the throttle back and voltage slowly drops back to acceptable levels. If I throttle up again without restarting the voltage will usually rise with RPM. Restarting the engine will occasionally stabilize voltage for an extended period.

I think the voltage regulator or rectifier is the cause. Problem is that the motor has the dual regulator and for the added expense I don't want to trial and error only to find out that it could be a corroded or loose connection. I have not found any yet.


jimh posted 01-09-2008 11:19 PM ET (US)     Profile for jimh  Send Email to jimh     
Brad--Electronic circuits are often affected by heat. Your description of the symptoms correlates well with increasing heat in the engine power head producing a malfunction of the voltage regulator.

I am not familiar with your engine. Perhaps you can mention the model year or epoch of its manufacture. My guess is that it probably has a permanent magnet alternator composed of an under-flywheel coil, a rectifier, and a regulator. Those three components are the major elements of the battery charging system.

If the output voltage of the charging system is not being regulated, it seems like a strong indication of a problem with the voltage regulator unit. I don't know if that device is integral with the rectifier on your motor.

One way to help isolate the problem would be to run the engine at idle but add heat to the regulator using a heat gun or hair dryer. If heat causes the voltage to drop out of regulation you will have a good indication of the source of the problem.

bear99 posted 01-10-2008 12:58 AM ET (US)     Profile for bear99  Send Email to bear99     

I honestly do not know the year of manufacture. I have a sales receipt from the original owner with a purchase date of 7/2/95 that says it is a "1994 new". That is what I always thought it was. If anyone wants to decipher the serial number and tell Me what year it is I would be grateful.

Heat gun is an interesting idea. I won't get a chance to try that until Saturday. I will report back then.


Tom W Clark posted 01-11-2008 09:25 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Serial number OG111433 indicates the motor is a 1994 Mercury 200.

Tom W Clark posted 01-11-2008 09:52 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Now this is strange. I go to Mercury Parts Express and enter the serial number for Brad's enginenand go through the usual rigmarole and select the page described as IGNITION COIL/VOLTAGE REGULATOR. I am taken to the exploded parts diagram along with the parts called out by part number, description of part, price and quantity per engine.

I can plainly see the voltage regulator in the diagram, it is part #7. Looking over at the parts list I see the line for part #7 and it is blank. No part number, no description of the part, no price but it does acknowledge that two of them are used per engine. It is noted as N/A which I take to mean Not Available, or perhaps No Longer Available.

What the hell? It would have been nice if the part number at least were present so one could cross reference it with some other source.

So I just happen to have the (hard copy) parts catalog for a Mercury 200, but it is for a 1989 model (actually Andy Gere's old catalog for the 200 he used to have.)

For fun I look up the Voltage Regulator and find the old part number. I than do what I always do when I am curious, I go to for a 2 second search and type in "voltage" "regulator" and the part number I have, in this case "18736A15"

A number of hits come up, none of them much help. I visit an Ebay store listed and see that this part is for sale for $400! Again, I have to ask: What the hell?

It also is clear this is not the voltage regulator that Brad needs for his 1994 Mercury 200. So I am now asking:

Is there anybody out there who can make sense of this, or more to the point, tell Brad where he can buy a voltage regulator for his 13 year old outboard motor, and preferably one that costs less than $400. God help him if he needs to buy two of them.

davej14 posted 01-12-2008 09:57 AM ET (US)     Profile for davej14  Send Email to davej14     
There is a used parts dealer in Ithaca, NY that literally has a barn full of used non-functional engines. All years and brands. He may have what you are looking for. If you can find the part number post it and I will look up his name & number so you can contact him.
bear99 posted 01-12-2008 11:50 PM ET (US)     Profile for bear99  Send Email to bear99     
Thanks for the link Tom. I also found out that My 20 horse Mercury kicker is a 1987.

Thanks Dave , I really don't want to recycle electrical components though.

Yesterday I pulled one of the regulators and got the serial number off the back. Reads 815279-3. The replacement CDI regulator is 194-5279. I need 2. Now it gets confusing , according to their chart My engine has a 16 amp charging system requiring only 1. Correct Me if I am wrong but I believe it is 40 amp. I guess it boils down to their chart being wrong or I am missing something as Parts Express clearly shows quantity 2.

Maybe I am over thinking this and I should just buy 2 and get on with my life.

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