Mercruiser Pinout Lists/Diagram

[76SeaRay]

Anybody have the pinout on the Mercruiser 8 pin engine connector? The 9 pin list would be great too...

 

[Scott Danforth]

diagrams are in the factory manual.

 

[alldodge]

Its actually a 10 pin and 8 pin. The 10 pin has 9 wires and the 8 has 8

8 Pin


This is with relay and reg


This is old BIA10 pin


This is new 10 pin

 

[76SeaRay]

Thanks, I am summarizing the info in a single spreadsheet for cross reference. In my restoration I have an 8 pin harness so I want to see what is not included in it that is included in a 9 or 10 pin harness. Trying to see what it takes to use what I have and wire up the new instrument panel. Once I get the spreadsheet done (this weekend) I will post it back here for confirmation. I will be running a 1996 GM 5.7L carb engine and Thunderbolt IV.

 

[76SeaRay]

Making slow progress. The 8 pin diagram above doesn't show the pin numbering in the round connector. So, I used my old harness to figure out the pin numbers. My harness doesn't have the same colors as listed above in the diagram.... Is there a old and new version of the 8 pin wire harness? Here is my 8 pin list with the colors and you will see it doesn't match the diagrams above:

1		Black
2		Tan
3		Brown
4		Orange
5		Purple
6		Red
7		Yellow/Red
8		Blue

Again, I am referencing the round engine connector pins using my engine to instrument panel harness. Any ideas? Thanks...

Oh yeah, I have a secondary instrument to engine harness (8 pin square to 8 pin square) that has Red (heavy gauge), Black (heavy gauge), White/Red, Pink, Light Blue, and Grey...

 

[alldodge]

No idea what motor and year

 

[76SeaRay]

I am scratch building what amounts to a 1996 Mercuiser 5.7L vortec with Thunderbolt IV, Rochester Quadrajet, mid riser dry joint manifolds (new) and full closed cooling system (new) to go into a 76 Searay restoration with Alpha One Gen One. Engine is ready to fire off on an engine stand except for harnesses to the instrument panel. I want to wire it up with the harnesses and instrument panel that will actually go in the boat. Wire harnesses I have are used from a different boat. So, trying to decide if I can use the harnesses or need to give up on those and find a different wire harness.

 

[alldodge]

Need to wire according to the motor installed and not the helm

A 1976 used an ampmeter and not a voltmeter. Suggest wiring using current configurations

Have the manual for a 76 Merc but none show wire listing you have. All show
1-Black
2-Brown
3-Green

 

[76SeaRay]

Hmmm, I am wondering if the 8 pin 20ft dash to engine extension harness I have is for a Mercury outboard and not a sterndrive.. Leaning toward scrapping this extension harness and look for a good used 9 or 10 pin harness. I have the extension harness with me but not at home right now and, unfortunately, I didn't bring either of the two engine harnesses with me to compare and see what those have for colors. The dash end is no problem as I can wire that as needed but I wanted to keep the engine end close to Mercruiser standard as possible for future engine servicing..

 

[alldodge]

Your new motor needs a 10 pin harness connector which has 9 wires in it. Pick up a 10 pin pig tail, cut the connector off yours

https://www.hardin-marine.com/p-132...-pigtail-mercury-plug-instrument-side-12.aspx

 

[76SeaRay]

My engine harness has a 9 pin connector on it. I picked up a 20ft NOS 9 pin engine to instrument panel extension cable and it fits great on the engine harness. So, I picked up a used 9 pin pigtail for the instrument panel end, however, it has 2 large pins and 7 small pins. My engine harness and the new extension harness has 3 large pins and 6 small pins.... Anybody know if there is a replacement connector available that I can create my own pigtail for the instrument panel end as all the used ones on EBay are the wrong type?

Thanks...

 

[76SeaRay]

Well, found a used 9 pin pigtail for the instrument panel end that has the correct pins... Looks like I am finally good to go on the wiring...