temp sensor wireing question

[bob johnson]

I want to button up all the wiring into my motor and seal it up while i am onto other wiring issues with my new boat. I have a bellows rubber boot I need to run everything through . I want to run a temp guage so I need to buy temp sending unit.( I think two one for each head..right?)

I want to run the wiring now...even though i dont have the senders yet.

will each sender needs its own wiring??

or do they combine?

if they need seperate wiring..can I ground to the motor nearby and only use a hot lead out?

I have assumed i cant use the temp sensor wiring for the alarm.......


which would be nice...

thanks....back to the boat work( sunny day here)

bob

 

[gss036]

Re: temp sensor wireing question

What type of engine are you referring to in this post, that would surly help. Normally, you have one temp sensor in the port head and an overheat sensor in the starboard. Sounds like you have a V-6 of some sorts. If there is a factory wiring harness running to the dash of the boat, I would think the wiring is already there.

 

[bob johnson]

Re: temp sensor wireing question

I have a 1997 evinrude ocean pro 90 hp

the wiring harness has two extra purple wires , two extra black wires, and extra gray tach sender wire....thats iut that doesnt go into a plug of some form( which all have mates and are accounted for what they do)

there is now a sender coming from the center of each head...on the one side there are two wires...on the other side the sender only has the tan/w blue wire.

I was told that those cannot hook up to my temp guage..they are only for an alarm....I want to buy temp guage sending units...so I can see what the temp is any time.

I see two open threaded ports for the senders on each head( although not centered...they are off to the left side of each head)

the boat is being wired from scratch....the motor is new to the boat.

I am trying to make this all work. I have picked up the guages i think i want..

and am trying to incorporate them into the evinrude factory motor harness and my new wiring for the boat.

it is a center console and I have the floor partially up and the console removed....need to finnish up the rear before i go onto the console and fuse panel and switches

thanks

bob

 

[gss036]

Re: temp sensor wireing question

I wish I could help more, but not familiar with the V evinrudes. Usually the tan/tan-blue are for temp senders. Wish you were close by as I have some old parts from my 200 Mercury that would probably work just fine. Find the Telflex site and check there, my short cut does not work and longer.

 

[Silvertip]

Re: temp sensor wireing question

If you have two senders on the engine you CANNOT combine them. They are reistance elements and paralleling two resistors of the same value results in a total resistance of 1/2 the value of either so the gauge cannot read correctly. What you can do is run a separate wire from each sender to a three pole switch. The center terminal of the switch feeds the temp gauge "S" terminal. You then flip the switch to select either right or left head. The only other option is to install two temp gauges.

Here are the two styles of temp senders. The silver one is a contact type and is mounted under a head bolt and contacts the head as close to the spark plug as possible. The other type screws into a water jacket port or it too can be a contact type using a separate mounting bracket. Make sure the senders are for an outboard.

 

[bob johnson]

Re: temp sensor wireing question

.... What you can do is run a separate wire from each sender to a three pole switch. The center terminal of the switch feeds the temp gauge "S" terminal. You then flip the switch to select either right or left head. .......... Here are the two styles of temp senders. The silver one is a contact type and is mounted under a head bolt and contacts the head as close to the spark plug as possible. The other type screws into a water jacket port or it too can be a contact type using a separate mounting bracket. Make sure the senders are for an outboard.

well, I went ahead and ran two seperate hot wires...so I will install two senders...just like the one you pictured on the right.

goes into what looks like it might be a straight thread, or a 1/8th pipe....not very large...maybe in the 5/16th dia range...

there are two of these female threads on the head that have nothing in them ...

I like the switch idea...i have an open bay in a panel for my contura rocker switches...

what is the lettering code for that type of switch..

ie: off -on= SPST




is it an ON-ON switch? SPDT( i think)

or an ON-OFF-ON

my colored horn wire was cut by the previous owner..and it is too close to the horn to splice back together..

so I wont have the warning horn working at all it looks like.

maybe just as well..the VRO was disconnected and I am guessing the low oil warning would constantly be going off.

so I want to have two senders for temperature.

got a lot done today....there is NO MORE room in that hose( the hose carrying all my engine wires , battery cables and water pressure hose) to feed anything else!!!!

did find a connector that I cant find a mating plug for..unless it got pushed under all the other wires deep down in the motor cowling.

it has two wires..one black the other tan with a black line

my Seloc book doesnt have color nor coding in the wiring diagrams for the engine.

the console harness is labled in the book, but not the engine harness.

I THINK it goes to the trim sender( from books wiring diagram)...but looking they dont match the colors I can see going into that sender

whew....thanks for any help

youll be proud with me when its done!! ha ha

bob

 

[jhebert]

Re: temp sensor wireing question

You do not need a three-pole switch.

The switch you need is called a single-pole double-throw or SPDT switch. This is generally noted as an ON-ON arrangement. If you want an OFF position you have to get a three position switch, with ON-OFF-ON arrangement.

For switch terminology see

http://en.wikipedia.org/wiki/Switch#Contact_arrangements

For information about color codes typically used in marine wiring, see

http://continuouswave.com/whaler/reference/wireColorCode.html

 

[Silvertip]

Re: temp sensor wireing question

The switch you need to switch between two senders is actually an ON-OFF-ON but the preferred switch would be a three pole (three terminals) that is on in both the up and down positions. Up the center and one other contact are connected. Down the center and remaining contact are closed. The gauge is connected to the center (common) terminal. Each sender connects to one of the other two terminals.