I Give up! is there no wiring diagram for my OB?

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
It's been days! searching for a wiring diagrams that matches my outboard... no luck (not even on maxrules) so I hope comeone can help me out.
I's a 1981 Mercury 40hp (2 cylinder) 2 stroke outboard, electric start.
I have found just about every darn 40hp diagram out there... except mine.
 

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
Yeah, that's the same one I found on maxrules.com... some of the colors don't match to what I have, for example, the previous setting had a yellow/bleck wire to the choke solenoid, this one has a Grey one. My grey wire goes to the rectifier.
My engine has an 8 pin connector
 

GA_Boater

Honorary Moderator Emeritus
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49,038
You have to know what you have before any manual works. 1981 is a crossover year and wiring harnesses/diagrams come in two flavors.

Early is the big side plug with 7 pins and late is the smaller internal plug with 8 pins.

AD's link, Page 2D-6 has his diagram. Matching colors anyway.
 

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
Serial number: 5750464

Wire colors on the remote side of the harnes are:
yell/red
yell/blk
grey
blk/yell
blk/yell
red
purple
salmon (goes to tach plug)
grey (goes to tach plug)
purple (comes from tach plug)
black (comes from tach plug)

Wire colors coming fro my ignition key:
yell/red
yell/blk
2 reds
2 purples
2 blk/yell
2 blacks
 

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
Mine has the internal plug with 8 pins, not the plug that goes thru the bottom cowl
 

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
"AD's link, Page 2D-6 has his diagram. Matching colors anyway"
Nope, not it either...
All I have found are for 3 or 4 cylinders, what I'm planning to do is to take the closest to my engine and take it from there with trial and error.
 

alldodge

Moderator
Staff member
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Mar 8, 2009
Messages
43,333
There are several pages of different diagrams, and if you paged thru and did not find yours then sorry.

Also have you look at boatinfo to see if another manual may have yours, there are several?
 

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
One step forward yesterday on getting this new-to-me OB to run.
The closest wiring diagram I have found is the 1984-90 50hp, serials 5579017 and above, except this is a 3 cyl diagram and my trigger doesn't have a violet, nor a blk/wht cable like the diagram shows... other than this, everything else seems adequate.

Yesterday I made a manual spark test, I turned the key on my remote to ON position (no battery connected), lanyard switch upwards, wrapped a rope around the flywheel and slightly pulled. I was happy to see I had a big'ol spark on both plugs (I checked one at a time).
Now my only concern is the BLK/YELL wire, it's not connected to anything cause I don't know exactly where it goes, I've read it could go where the BLUE stator wire connects to the powerpack, or where the TILT switch connects to the powerpack.

Next step would be to connect the battery and add fuel to the mix to see if my control wiring is correct and also see if the OB purrrs!
 
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