regulator problem?

[twinsfan]

I have a 1979 90hp inline 6 mercury outboard. serial number 5372888. I keep getting a high voltage signal on my depth finder and am wondering is this because my regualtor is bad? My tach works all the time and battery appears to charge so i ruled out the stator is this also correct? Thanks in advance for feedback.

 

[Barnacle_Bill]

Re: regulator problem?

According to the schematic I have for that motor, you do not have a regulator. I had the same problem with my 83 150. I even blew 2 <br />Garmin 240,s before I realized what I was doing. (I didn't tell Garmin that). My fix was to run my sensitive electronics off my trolling motor batteries. You can turn more electical things on to get it down. Or for about $140.00 you can get one of the combination rectifier/regulator units and install it.

 

[ronmold]

Re: regulator problem?

I've posted this before and saved it, here it is again:<br />Here's how older merc charging systems worked: The stator, generally a 4 to 9 amp unit, puts out an AC voltage on it's 2 yellow wires that vary in voltage (and frequency this is where the tach lead comes from) according to the motor RPM. This AC is converted to DC by way of the rectifier which is 4 diodes in a "bridge" configuration. This voltage also varied as to the RPM. Merc's original design used the fact that the battery acted as a load, always taking a few amps even when charged. This few amp draw shorted the output of the low-amp stator enough to cause almost "self-regulation" of the charging system output, hence many of the older motors had no regulator. With battery technology improving (less full-charged draw) and the need for more amps because of all the new marine electronics available, the motors started coming with higher output stators and the battery couldn't self-regulate anymore. Merc started putting on a regulator (you don't have one) that would sense the DC voltage from the rectifier and short one of the yellow stator leads to ground when the voltage got too high. This along with the battery draw would keep voltage constant. Problem with this is if a battery post loosens and doesn't take some of the extra amps, or you put on a CDI high-output stator, that sorry regulator has to do overtime work and fries! CDI makes a great unit #194-5279 that rectifies and regulates, not by shorting out the yellow leads but electronically by just shutting off the charge circuit when the battery voltage is at 14 where it should be. This keeps the stator much cooler also. Hope this helps.<br />About $95 from http://www.seilermarine.com/rapair/mercury.htm <br />Hope this helps.

 

[twinsfan]

Re: regulator problem?

Thanks for the info i think i will just run the graph off a seperate battery to eliminate problem.

 

[Chris1956]

Re: regulator problem?

Twinfan, You can also install a 14 Volt Zener diode, if you can find one in a 6Amp or larger capacity. This simple (and cheap) voltage requlator will short all voltage above 14 volts directly to ground.<br /><br />Zener Diodes are not as available as they once were, but Radio Shack or an electronics shop may have one!