1987 mercury black max 135 hp rectifier wiring question

[theboatman69]

Hello all,
So i know that rectifiers have been beat to death. I have read the forums. So let me just start here. I bought a used boat, 1981 Deltacraft 170 xlt with a nice running 1987 mercury black max 135hp outboard engine. The tach was not reading. So after reading forums i discovered that the rectifier must be screwed or stator. When i took the cover off to examine the rectifier, I discovered it was wired wrong!!! Very wrong. On the 2 AC terminals the 2 yellow wires were tied together on one terminal, the grey wires was just tied to one terminal with a yellow/ red stripe wire? and there are 2 red wires on the positive terminal So i did a diode check, fixed the tach and now its reading. Now the wiring has one yellow, and the grey tied on one post, one yellow on one post, 2 reds on the positive post but my question is where does the yellow/ red stripe wire go? when i trace it, it goes up to what i believe is a regulator or maybe idle control box (but im probably wrong). It has the red wire from the positive terminal of the rectifier, and the yellow/ red stripe wire on it. PS the color might me faded. its a lighter color than the yellows so maybe a white and red stripe or black stripe faded to red?? Thank you for taking the time to read this.

 

[theboatman69]

Update: after looking at parts diagrams i realized it is in fact a voltage regulator. So can someone tell me the correct way the rectifier/regulator should be connected?

 

[Glastron_V210]

Try here:

http://www.maxrules.com/mercwireindex.html


They have lots of good info. It's serial number based so I didn't try to look one up for you.

The grey is the tach for sure, and should be tied to one of the yellows for sure (AC stator output).

Here's the thing, the yellow/red is the oddball. I have seen on other outboards that they have dual stator outputs.

Sometimes the yellow/red will be a center tap, in which case it would not be used. Sometimes it is tied to the end of both coils, and the other ends (the yellows) are paralleled together (Sounds like maybe that's what's going on here).

What I would do is verify there is a coil between the two yellows, or between the yellow and yellow/red etc.

You may be able to use an ohm meter.

Maybe a better way to do this is check for AC volts with the engine running. Check between each set of wires to find the outputs. This depends on some skill level with a meter and electrical knowledge.


Chay

 

[Glastron_V210]

Need a picture!!

Chay

 

[theboatman69]

Try here:

http://www.maxrules.com/mercwireindex.html


They have lots of good info. It's serial number based so I didn't try to look one up for you.

The grey is the tach for sure, and should be tied to one of the yellows for sure (AC stator output).

Here's the thing, the yellow/red is the oddball. I have seen on other outboards that they have dual stator outputs.

Sometimes the yellow/red will be a center tap, in which case it would not be used. Sometimes it is tied to the end of both coils, and the other ends (the yellows) are paralleled together (Sounds like maybe that's what's going on here).

What I would do is verify there is a coil between the two yellows, or between the yellow and yellow/red etc.

You may be able to use an ohm meter.

Maybe a better way to do this is check for AC volts with the engine running. Check between each set of wires to find the outputs. This depends on some skill level with a meter and electrical knowledge.


Chay

Thank you for your reply Chay

You see the thing is the yellow red wire is independent of the stator. There are 2 wires running from the voltage regulator. A red wire and the yellow red wire (which i believe is white and red now just discolored). After slogging over forums all day i found that the voltage regulator is NLA and from what i can tell it isn't needed. When i test with the engine running at the rectifier, the voltage rise is sloooooowwwwww I increased the rpms a little and it starts to rise (as im just using muffs and a garden hose). about 13vdc at the positive terminal. I did a diode check on the rectifier and they seemed good. Does this sound correct?

 

[theboatman69]

I tried to upload a pic and they were "too big" from my phone.......Im new here lol

 

[theboatman69]

Darn it i resized but it says im not authorized to post them

 

[theboatman69]

got it!

https://ibb.co/c1xqha
https://ibb.co/mGjsvv

 

[Dukedog]

chunk tha reg and done... good battery upkeep is key..

 

[theboatman69]

Thank you all for your advice. I really appreciate it. I took the regulator out of the circuit and the rewiring is now charging my battery just fine. Thank you guys!