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Honda BF50 (5hp) Wiring

gannet586

New member
I have an old 5hp BF50 that I'm trying to resurrect. It's been sitting for a while, and at some point mice got into the motor and chewed a couple wires off. I'm trying to sort out where they go. I believe one goes into the oil light, and the other goes into the motor handle, but I can't sort out which goes where. Wire "2" in my pictures has 1 wire with a red stripe 1 wire with a yellow stripe in the same jacket, and wire "1" in my pictures just has two solid black wires in the same jacket. So my question - Does wire 1 go into the oil light, or into the motor handle? I haven't found any good pictures of this motor online that would show where those wires are meant to go. Thanks
motor wires 1.jpeg
motor wires 2.jpeg
 
Hi,

I don't have the wiring diagram for your outboard and couldn't readily find one online so I can't give a definitive answer.

I do know that, typically, red with black wire (or black with red) is often the emergency stop switch circuit. So, that would have that wire going to the tiller in that case.

Solid black wires for small Hondas are almost always ground but what components those two wires go to is impossible for me to guess.

The only reference I could find for yellow/black or black/yellow is for the regulator/rectifier. That might be true if your outboard has a charging receptacle.

If you want to know for SURE, you can order the official shop manual here:


If you do want the manual, make sure that you take care making your selection as it looks as if there is more than one choice for the 5hp model.

Hopefully someone else here has what you need to know.

Good luck and welcome to the forum.
 
Thanks @jgmo, that was helpful in setting me on the right path. I hunted down a PDF of what I believe is the correct manual for the BF50 5hp. Here is the wiring diagram - it does show a black/red wire and a black/yellow wire going together into the oil light, so I think I'm sorted there. However, it shows a black/red wire and a black wire going into the engine stop button.

My problem being that those two wires are both all black in my motor, no red on either of them. From the diagram, I can see which black wire is the ground, and which black wire is live, however that leaves me wondering which side of the engine stop button they actually plug into. I might be able to match up the mice chewed wires :)

As a side - do you know if these motors will run with the oil lamp and the engine stop button wires disconnected as they are?

Screenshot 2025-10-16 at 1.29.03 PM.png
 
Yes, the engine should run with those wires disconnected but you'll need to ground the black/red wire to shut it off.
 
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