Johnson 70 HP Control Box

[CJY]

Hello all,

I am in the process of installing a new tach on my boat w/o any harness.

I opened up the control box to find the correct wires and found something that puzzles me. Right above the key ignition switch in the control box there is a little black electrical box. The box is approximately 1-1/2" wide by the same across. On the box, there is a "+" connection. It appeared to at one time have 2 purple wires connected to it on the positive side with a single brown wire coming off the other. Both purple wires and the brown wire have been disconnected and all 3 wires have their connections taped over with electrical tape.

Any thoughts as to what this is, why it may be disconnected and what may happen if I reconnect the wires?

I believe the purple may be ignition, but what did someone want to keep from operating and why?

Thank you for any help.

 

[gyoung]

Re: Johnson 70 HP Control Box

Sounds to me like the box is the warning horn.

The purple wire is +12 volts when the key is on. It supplies power to accessories like the warning horn, tack, hour meter, etc. The tan wire is the ground wire for the alarm system. It completes the circuit to ground to sound the horn when an over temp, low oil or VRO fault occurrs.

Hope this helps.

 

[F_R]

Re: Johnson 70 HP Control Box

Kill that #%&*!@@ noise. It's keeps a guy awake. Let'er burn.

 

[CJY]

Re: Johnson 70 HP Control Box

Thanks gyoung. This is the third year I have owned the boat and the alarm sounds when inserting/turning the key as it always has.

 

[gyoung]

Re: Johnson 70 HP Control Box

CJY

Is the alarm coming from the control box, or has another horn been re-mounted externally?

My boat is at the cottage so I can't check, but I think the alarm that sounds when you turn the key on has also a black ground wire connection for the electronics in the alarm that creates the beep when the key is turned on. You describe only two wires which is the old style horn that didn't sound with key on. I suspect it has been disconnected and an updated horn installed external to your control box.

Have you tested the over-heat alarm and VRO alarm (if you have one) by sliding the boot off the tan wire connectors under the engine hood and grounding on the engine?

What year is your engine? I'm assuming it's similar to my 1985 70hp and that you have the standard OMC control box.

 

[CJY]

Re: Johnson 70 HP Control Box

The motor is an 1989, 70 hp.

Yes, the alarm is coming from the control box. I have also tested the vro alarm as well, well not on purpose, but if the oil stops flowing the alarm from the control box does sound.

 

[gyoung]

Re: Johnson 70 HP Control Box

OK. Sorry I'm out of ideas then.

Maybe someone else can help you.

GY

 

[throwback2332]

Re: Johnson 70 HP Control Box

The wire should be gray for the tach signal, purple is the tach power and you will need to ground it also