Curiosity question 1978 Johnson 85 hp

[clemsonteg]

I have been doing some work on this motor here and there as the season goes on. I noticed there is a wire embedded in the each head in between the plug wires. What is this wire for? It isn't causing any issue I'm just curious.

 

[Daviet]

Re: Curiosity question 1978 Johnson 85 hp

If they have tan wires, they are your temp senders.

 

[clemsonteg]

Re: Curiosity question 1978 Johnson 85 hp

If they have tan wires, they are your temp senders.

I think they are tan. Are they senders for a gauge or for the cdi to cut power if it gets overheated?

 

[Daviet]

Re: Curiosity question 1978 Johnson 85 hp

Without looking at a manual, I beleave the tan wire sensors were for temp only, made the horn go off when hot.

 

[wilde1j]

Re: Curiosity question 1978 Johnson 85 hp

NOT for a gauge. They are temp switches for alarm only.

 

[clemsonteg]

Re: Curiosity question 1978 Johnson 85 hp

NOT for a gauge. They are temp switches for alarm only.

They have no purpose in my case then. No gauges, no horns. Like I mentioned, I was just curious. I figured it had to be a temperature sensor of some sort

 

[Daviet]

Re: Curiosity question 1978 Johnson 85 hp

Are you using a factory control box, that's where the horn is located. You should have some type of system that tells you if your engine overheats.

 

[HighTrim]

Re: Curiosity question 1978 Johnson 85 hp

Grounding the wires should sound the overheat alarm in the control box as mentioned. Pretty important feature.

 

[clemsonteg]

Re: Curiosity question 1978 Johnson 85 hp

Grounding the wires should sound the overheat alarm in the control box as mentioned. Pretty important feature.

I'm using an omc control box. Didn't know there was a horn inside. That's good info to have

 

[Daviet]

Re: Curiosity question 1978 Johnson 85 hp

As HighTrim suggested, you should test the horn every once in awhile, I do it at least twice a year to make sure it works. Just turn the key to on and ground the harness end of the sensors to ground and the horn should sound off.