head temp. sensor

[iggyw1]

I purchased a temperature guage and a temp. sending unit that is matched to the guage. The sender is an external sensor that is going to be mounted onto one of the head bolts and the sensor will be touching the head cover on the outside. There were no instructions for wiring the thing. The gauge has three connections on it, I (ignition) S (sender) and G (gound). If I understand this correctly, there is only one wire that I have to run from the sensor that is on the motor to the gauge that is on the dashboard of the boat, correct? The Ign. wire and ground can be wired at the key switch and a good ground that I have under the dashboard. The sensor itself will be grounded where it is mounted to the head cover bolt? And I also understand that I should remove the paint at the motor where the sensor will be touching.
It is going on a 40 h.p. 1962 Evinrude, model 35933.
Thanks for any tips on this installation!

 

[MJS]

Re: head temp. sensor

Not sure if you have to remove the paint because it is grounded through the bolt into the head, but the rest is correct. I mounted mine on the side rather than the head because of the head cover not being flat. It had ridges and would not get good contact. The "I" connection should only be hot when the key is turned on.

 

[phillnjack2]

Re: head temp. sensor

where did you manage to get the sender and guage ?
how much was it ?

i think this is a great idea to have a temp guage, much better than just an alarm as you cannot see the
engine getting too hot untill its realy too late.
The alarms come on when the engine is way way over heated, almost to the point of the engine destruction.
i realy want to fit a guage and temp sender but am having no luck finding one.

as long as you get a good solid contact with the cylinder head it will work fine.

post photo's of your guage and sender if possible ,

phill

 

[emdsapmgr]

Re: head temp. sensor

The sender will also get the ground from the metal bracket that holds it to the head. You can remove the paint just under the flat tip of the sender, but heat will transfer through the paint even if you don't remove it. Should work just fine. I'd probably not wire the sender - + through the key switch. The fuse in the main engine wiring harness is only a 20 amp fuse. It can accept a direct-wired tach, but I'd keep all other accessores wired through the main boat wiring harness at the dash- where the rest of the gauges and lights are wired. If you overload the engine's key switch (like with the bilge pump, horn, radio, etc.), the main wiring harness fuse can blow, causing you to lose the electric starter and power trim functionality.

 

[MJS]

Re: head temp. sensor

I'd probably not wire the sender - + through the key switch. The fuse in the main engine wiring harness is only a 20 amp fuse. It can accept a direct-wired tach, but I'd keep all other accessores wired through the main boat wiring harness at the dash- where the rest of the gauges and lights are wired. If you overload the engine's key switch (like with the bilge pump, horn, radio, etc.), the main wiring harness fuse can blow, causing you to lose the electric starter and power trim functionality.

good call

 

[phillnjack2]

Re: head temp. sensor

yes agree with the statement about not running through engines wiring.
Not too hard to run a nice strong wire from the battery and make a nice block up under the dash for any extra stuff.
Lights radio, phone charging socket,vhf,fish finder,and all sorts with a nice fuse panel as well.
it can all be on a seperate cut-off switch as well.


phill

 

[dazk14]

Re: head temp. sensor

Does the gauge have a light? The gauge itself through to the thermistor on the power head draws very low current and can be connected directly through the ignition switch.

 

[Silvertip]

Re: head temp. sensor

The sender will also get the ground from the metal bracket that holds it to the head. You can remove the paint just under the flat tip of the sender, but heat will transfer through the paint even if you don't remove it. Should work just fine. I'd probably not wire the sender - + through the key switch. The fuse in the main engine wiring harness is only a 20 amp fuse. It can accept a direct-wired tach, but I'd keep all other accessores wired through the main boat wiring harness at the dash- where the rest of the gauges and lights are wired. If you overload the engine's key switch (like with the bilge pump, horn, radio, etc.), the main wiring harness fuse can blow, causing you to lose the electric starter and power trim functionality.

Instruments on the console are NOT wired through the boat harness. They receive power from the "A" terminal on the ignition switch. If they are powered from the boat harness a separate switch would be needed to turn the gauges on and off -- which is a ridiculous way to do that. The 20 amp fuse at the engine is more than enough to power any added gauge since instruments draw very little power. The temp gauge also has an internal light that gets wired to the NAV side of the NAV/ANC light switch. Yes -- there is only one wire to run from the sender to the "S" terminal on the gauge.

 

[iggyw1]

Re: head temp. sensor

Thanks all. Phillnjack, I got the gauge and sender from Faria instruments (on line) I went to the "discontinued" gauges and got a temp gauge for only $10.00. The sender was also $10, but had to call the place and order that. The gauge and sender need to be matched with each other. The sender is not on their on line catalogue.

Also, I did run a good wire direstly from the battery and put a fuse block up front under the dash for the radio, cigerrette lighter (f0r the spotlight I have) the horn, etc. The new temp gauge has to be wired in with the ignition I would think if I want it to go off with the key off.
Thanks everyone for the input! It all helped.

 

[iggyw1]

Re: head temp. sensor

dazk14, to answer you too. Yes, the gauge has a light, however, it is made in such a manner that I can run a jumper to the light connecter on it or not.(Frome the ignition post on the gauge itself). I was not going to run the hot wire to it so the light will not be on at any time. If I need to see the gauge at night (which is hardly ever) I will just shine my flashlight at it. The only other gauge that I have and it too does not light up is my volt meter.

Thanks.

 

[powrguy]

Re: head temp. sensor

dazk14, to answer you too. Yes, the gauge has a light, however, it is made in such a manner that I can run a jumper to the light connecter on it or not.(Frome the ignition post on the gauge itself). I was not going to run the hot wire to it so the light will not be on at any time. If I need to see the gauge at night (which is hardly ever) I will just shine my flashlight at it. The only other gauge that I have and it too does not light up is my volt meter.

Thanks.

I installed the temp gauge on my motor (90HP V4), and I used a jumper to an adjacent gauge for the lighting, which is on the switched hot supply from the ignition. Better to have the temp gauge ALWAYS in service when the motor's running, and the light is not a big current draw, so ignition supply is fine. Also, you are correct in that you only need that tan wire to the gauge (usually included with the gauge itself, most often) and just run it up to the S (sender) terminal on the gauge.

I don't trust idiot lights, or horns, as it may be too late, and you get an indication of problems early, once you have a baseline temp reading that your motor usually runs at.

 

[iggyw1]

Re: head temp. sensor

I agree powrguy. The idiot light that I currently have will go on if the motor is 'hot' and I want to know it's 'getting hot' before it gets hot! I am adding the gauge so it will be an indicator to let me know what is happening in the motor as far as temp is concerned. Someone said the gauge may not be accurate. It really does not matter to me if it is accurate or not when it comes to the true temperature. If it starts out at indicating 150 degrees and it is actually 140 degrees (don't think it would be that far off anyway), that is fine with me as long as the temperature gauge will tell me i IF the motor temp goes up to 160 per gauge, than I know there is something going on. Thanks for your input.

 

[powrguy]

Re: head temp. sensor

I agree powrguy. The idiot light that I currently have will go on if the motor is 'hot' and I want to know it's 'getting hot' before it gets hot! I am adding the gauge so it will be an indicator to let me know what is happening in the motor as far as temp is concerned. Someone said the gauge may not be accurate. It really does not matter to me if it is accurate or not when it comes to the true temperature. If it starts out at indicating 150 degrees and it is actually 140 degrees (don't think it would be that far off anyway), that is fine with me as long as the temperature gauge will tell me i IF the motor temp goes up to 160 per gauge, than I know there is something going on. Thanks for your input.

I installed the Teleflex temp guage with the sender (it has a bracket with the sending unit, that attaches with one of the head bolts).

I checked the gauge reading against a thermo-gun, and it was within a couple degrees of the temp reading on the gun, on the gauge, so it's pretty good.

 

[iggyw1]

Re: head temp. sensor

Thanks for the info. I will be installing mine on my motor tomorrow, and I'm sure I will feel a lot more comfortable with the gauge opposed to having the light that goes on "too late" to let me know my motor is hot. lol Thanks!

 

[w2much]

Re: head temp. sensor

Glad you got your info iggyw1. Good idea to install this unit. Now I am going to jump your thread as long as you have garnered so much attention.
I have often thought of installing a temp sender and gauge as you have. You have one head on a two cylinder motor. thus one sending unit and gauge does the job .
I have a 60 degree six cylinder that overheated on one bank last year. Would it be proper or called for to install two of these sending units ,then two gauges one for each bank for it to be of any real use. If only one sender is used on a V block what good will it do?

 

[dazk14]

Re: head temp. sensor

Glad you got your info iggyw1. Good idea to install this unit. Now I am going to jump your thread as long as you have garnered so much attention.
I have often thought of installing a temp sender and gauge as you have. You have one head on a two cylinder motor. thus one sending unit and gauge does the job .
I have a 60 degree six cylinder that overheated on one bank last year. Would it be proper or called for to install two of these sending units ,then two gauges one for each bank for it to be of any real use. If only one sender is used on a V block what good will it do?

As you have deducted, you need 2 gauges and 2 sending units to do it correctly. Each head will have a location for a threaded thermistor (sending unit).

 

[iggyw1]

Re: head temp. sensor

That would make sense that you would need two sensors & two seperate gauges on your motor. Like you stated, would good would it do to just have one sensor on a V block motor? Seems like a very EZ hookup to me, and it would be worth the extra money to know before the motor actually gets hot.

 

[sullyboy]

Re: head temp. sensor

:facepalm:Ok here we go everyone shoot lame duck in the water!! Reading the blogs you say high temp sensor & gauge the sensor bolts to the cylinder head right? right. Ok here goes the duh are weee talking about a water temp gauge???? beause I cannot find a head temp gauge on line:redface:
Sullyboy

 

[minuteman62-64]

Re: head temp. sensor

:facepalm: beause I cannot find a head temp gauge on line:redface:
Sullyboy

I found mine at Jamestown Distributors.

 

[iggyw1]

Re: head temp. sensor

:facepalm:Ok here we go everyone shoot lame duck in the water!! Reading the blogs you say high temp sensor & gauge the sensor bolts to the cylinder head right? right. Ok here goes the duh are weee talking about a water temp gauge???? beause I cannot find a head temp gauge on line:redface:
Sullyboy

I got mine at Faria instruments (on line), but they did not show the sending unit that goes with the gauge on line. I called them and inquired about it and they sent me the sender (temp sensor) that is calibrated to the gauge that I purchsed. (the two pieces MUST be matched to get a true temp I was told by them). The temp gauge is just that "a temperature gauge" which I believe will register the temperaure whether it is water temp OR head temp. The gauge is in the dashboard while the sender (TEMPEARTURE SENSOR) is attached to the a head bolt on the motor and is in contact with the head cover on the motor and sends the temp of the head 'with an electric singnal' via one wire from the sensor the the gauge. I bought a discontinued gauge for $10 and the sensor was also $10. All I needed to buy extra was some wire for the connections.

NOTE" Faria does not handle retail sales. If you have a friend that owns a company, he can order from Faria direct.. They will sell wholesale only. West Marine (if you have one near you) sells Faria Products, and they may sell Faria products at iboats.com as well, and I'm sure there are many reputable retail dealers out there that sell Faria pruducts. And I know Teleflex has the same type gauge /sender that I purchased from Faria. But again, I do not think there is a defference between the head temp gauge and the water temp gauge, just the sending unit (at the moror end) would be the difference.