[micjo]

My 1996 Mercury 135 has the two voltage regulator system. My tach has started to quit working then start working intermittently. I figured the regulator/rectifier was going bad. I discovered it had two of them. I asked my local Merc dealer and he said I should replace both regulaters as a set. At $325.00 for two (parts only), he said he could rewire the existing wiring for $55.00 and not have to replace either regulator. Does one regulator run the tach and the other run the charging? Can he really do that??? What rewire fix is he talking about? Has any one heard of this fix. Or is this a cobbled repair??

[Chris1956]

That motor has two independent 20A charging systems. I suspect he was planning on moving the tach signal wire over to the good VR and removing the bad VR, leaving a single 20A charging capability.

CDI Electronics makes replacement VRs. They are avail at many places on the web. Check the VRs for burning or discoloration. You can move the grey tach signal wire to the good pack and remove the bad one, or buy a replacement VR.

A lot of times the second VR will fail shortly after the first.

It is said that the CDI VRs are better than OEM.

[micjo]

Thanks for the quick response tip. I could do that switch to the good reg myself and save the $55. I suspected that was the repair he was going to do. But doing only the tach wire switch and not replacing the bad reg I'd only have 20 amps of total charging instead of 40 amps correct? Can that bad reg still have good dc output just not tach voltage? I've got a lot of electronics drawing off the starting battery, even though I have a onboard battery charger that is a three bank that charges the start batt. would it be better to replace the one bad reg now and replace the other if it fails later? Or will one bad reg take out the other in time? Thanks for your expert information............Steve

[j_martin]

Originally Posted by micjo

Thanks for the quick response tip. I could do that switch to the good reg myself and save the $55. I suspected that was the repair he was going to do. But doing only the tach wire switch and not replacing the bad reg I'd only have 20 amps of total charging instead of 40 amps correct? Can that bad reg still have good dc output just not tach voltage? I've got a lot of electronics drawing off the starting battery, even though I have a onboard battery charger that is a three bank that charges the start batt. would it be better to replace the one bad reg now and replace the other if it fails later? Or will one bad reg take out the other in time? Thanks for your expert information............Steve

When the tach goes, the regulator is almost always shot.

Move the tach wire to the other one and see if it works. If it does, disconnect the first regulator (tape off both the red and yellow wires) and go looking for replacements. You can run on 20 amps in the meantime.

New, I'd go CDI. Used, look for the black 6 wire mercury regulators with the black potting. They're pretty good too. You can replace one at a time. It shouldn't be a problem, even if the other one goes later. If you have a pretty good load, like lots of electronics, or you anchor and run off the battery for long periods running the battery down, theoretically shouldn't hurt a single regulator. Only problem is the regulators can't read or understand theory.

Often the yellow wire (stator) bullet connectors relax and heat up, and the heat travels down into the regulator and stresses it. Fix is to at least replace the connectors. I solder and shrink wrap the connections.

hope it helps
John

[micjo]

Thanks for the info John. It really helps a lot towards solving this problem. You folks out there who take the time to respond to our questions really deserve a big THANK YOU!!!!!!!............Steve