What does the wire to the top-left of the top cylinder do?

[rebuilt]

'82 35hp 35ELCND. Bought used. Heard it run. It sounded good. I'm cleaning up some burnt and corroded wiring on the motor. Mostly grounds.. There is a small brown wire that is attached to some sort of sensor that is located to the top left of the top cylinder. It goes into a rubber boot. What does this wire do? Guessing cylinder head temp? It's corroded all the way back to the large coupler that feeds the harness to the ignition switch. I'm trying to restore all functionality to this motor. I bought the book for the motor from Iboats, but can't find this wire or a diagram. Seloc was no help on this one. Thanks, KR

 

[Walker]

Re: What does the wire to the top-left of the top cylinder do?

Temperature sensor connected to your warning horn for overheat

 

[WillyBWright]

Re: What does the wire to the top-left of the top cylinder do?

Basically yes. It's an overheat switch that feeds the hot horn as opposed to a temp sensor that would feed a gauge.

 

[rebuilt]

Re: What does the wire to the top-left of the top cylinder do?

Can I feed it to a guage? KR

 

[ddennis]

Re: What does the wire to the top-left of the top cylinder do?

If I am not mistaken those sensors only cut on at a preset temp (and thus sounding the horn)..they do not send out a continuous "how hot am I " signal that a guage could use. You could add an aftermarket temp guage and sensor, and keep that one also.

 

[Walker]

Re: What does the wire to the top-left of the top cylinder do?

Won't work on a temp gage. The sensor is either on or off.

 

[Big Keepers]

Re: What does the wire to the top-left of the top cylinder do?

My boat had a temp gauge sender on it. Very simple to install. It was a metal post shaped thing with threads on it. You mounted a small metal bracket usually by putting a water jacket screw through it. The small sender screwed down on the bracket onto the head surface. It sends the signal with a wire to the gauge. The whole thing was no bigger than any other small part on the block.

 

[rebuilt]

Re: What does the wire to the top-left of the top cylinder do?

So the way OE rigs it, it's like an idiot light in a car. Thanks for the info. KR

 

[MiKeC.]

Re: What does the wire to the top-left of the top cylinder do?

I have a 115, I have the same wire hanging out. Does that wire go directly to the horn, no ground?

 

[F_R]

Re: What does the wire to the top-left of the top cylinder do?

Yes it does. The temp switch completes the ground return through the head.

We appreciate ya and are glad to help with your questions, However please start your own thread in the future. Less complications without threads going off in a bunch of different directions.

 

[MiKeC.]

Re: What does the wire to the top-left of the top cylinder do?

Thanks, will do.

 

[CharlesW]

Re: What does the wire to the top-left of the top cylinder do?

One other thing about that sensor wire.
If you ground it to the motor for a second or two with the ignition switch on but the motor not running, it should sound your warning horn as a check to be sure it is working.