Questions on installing new Mercury outboard

[DirtMcGirt]

Hello! I recently purchased a brand new 40 HP Mercury jet outboard and am trying to install it myself on my bass tracker boat. I purchased the side mount remote control for the motor.

I am in the process of disconnecting my old motor(Johnson) controls and noticed a few things. My new control box has 2 extra wires dangling... Both are of the tan color. According to diagrams those are for temp sensors/warning horn.
- My old controls do not have any wires that would connect to these... How should these wires be hooked up?

I also noticed that there is a separate smaller wire harness that comes out of the bottom of control box. Research indicates this is for the gauge or gauges.
- My question is what gauges will work off this harness... And second.. what harness connects to the control harness to go to my gauges? My dash currently has a tach, volts, fuel, and speed. In researching... Would this be the correct model for the harness... The plug looks similar: 84-879978t1

For reference here is my side mount controls: 881170A13

I just want to make sure I am getting the correct parts and installing everything correctly. Any help would be appreciated... Bc I'm ready to fish!!

 

[Don S]

Re: Questions on installing new Mercury outboard

Have no idea what a 84-879978t1 plug looks like, can you post a picture?
Is your motor a 4 stroke EFI or carbed? SN would really help.

I know the control is a 4000 side mount. Do you have smartcraft on it?

 

[DirtMcGirt]

Re: Questions on installing new Mercury outboard

Plug looks similar to this:
Tracker Mercury 84-879978T1 Smartcraft Boat Gauge Speedo Wiring Harness | Great Lakes Skipper

Motor is EFI

Motor SN: 1C221619
Model: Jet40 4S EFI

I'm uncertain about the smartcraft option... Is that what the extra sire harness plug is for?

Thanks for your response!

 

[Don S]

Re: Questions on installing new Mercury outboard

I'm uncertain about the smartcraft option... Is that what the extra sire harness plug is for?

Thanks for your response!

Yes, that harness you linked to would go from the motor to the Smartcraft gauges (Not the same as your analog gauges).

Here is the wiring diagram that shows how it goes together with your control.

View attachment Remote control.pdf

If you want to use your present gauges you just disregard all the Smartcraft stuff in the diagram.
There is another harness for the 5 pin tachometer harness. 84-86396A8 is the tach harness (4 ft long), 84-86396A24 is the same but 13 ft long.
It would give you power and ground for fuel gauge.

 

[DirtMcGirt]

Re: Questions on installing new Mercury outboard

Thank you Don.. that does help. Yes, I do plan to keep using my analog gauges. The wire harness part number you gave... Where does that plug in at.... Reason I ask is that I'm not sure I have a connector on my control that looks that way. Please let me know if I am not visualizing the setup .... Or following the diagram correctly.

Thanks again!

 

[Don S]

Re: Questions on installing new Mercury outboard

The wire harness part number you gave... Where does that plug in at.... Reason I ask is that I'm not sure I have a connector on my control that looks that way.

In the wiring diagram, it plugs into the tachometer harness (item 12).
Then you can just cut the harness to fit, and use the wires you need.

I did this drawing for another guy, changed some wire names and it works for yours.