temp guage not working

[imraan47]

Hey.
OK so temp gauge is not working for a while now and i should really fix that.
I tested the gauge and its working fine.
to test i took a small wire and hooked G and S and the gauge went to max
the gauge just sits at the first line (cold)
is there a sender or something like that on the engine and where is this located? i have no clue how this gauge is hook up. all i know it goes into the main harness onto the engine but beyond that i have no idea where to look. manuals don't even tell me.
i have #10 manual

 

[Reming870]

Re: temp guage not working

The sender is located on the engine right below the thermostat if this is on the boat in your signature. Make sure the sender is grounded properly. Someone installed mine with teflon tape which created a boundary to ground.

 

[imraan47]

Re: temp guage not working

here is a pic of engine area...can you point me more closer to it. i dont know the parts on this engine all too well. i know the main stuff like alternator, carb, starter oil filter, fuel filter
where is the termostat?

http://i14.photobucket.com/albums/a304/imraan47/IMG_0546.jpg

http://i14.photobucket.com/albums/a304/imraan47/IMG_0237.jpg

http://i14.photobucket.com/albums/a304/imraan47/whtsthis.jpg

 

[JWebber]

Re: temp guage not working

Should be at the vary front part of your engine where the hose distribute to and from. You will see some wire going to a sensor.

 

[imraan47]

Re: temp guage not working

ok yea i figured out where the thermostat is. i remember when winterizing boat. i will go check now and see whats going on there.

 

[Don S]

Re: temp guage not working

.

 

[imraan47]

Re: temp guage not working

just checked the wire. it was grounded all nice but i took it off, cleaned it up alittle and sprayed some wd40 and secured it properly.
i guess the termostat is busted then? how much should that cost me?

 

[scv76]

Re: temp guage not working

just checked the wire. it was grounded all nice but i took it off, cleaned it up alittle and sprayed some wd40 and secured it properly.
i guess the termostat is busted then? how much should that cost me?

The wire should not be grounded, it should only contact the stud on the sender unit. The sender unit is grounded via the threads where it screws into the manifold.
If you have and know how to use an ohm meter, disconnect the wire from the sender unit and connect your ohm meter between the stud and a good ground point. With water going through the sterndrive start the engine and watch the resistance change (goes lower) as the engine warms up.
You can also use the ohm meter (will need an extension wire to do this) to measure from the disconnected wire (the one you took off the sender unit) to the point where it goes to the dash gauge. This measurement should have almost no resistance. The wire from the sender unit goes through the main wiring harness connector, and somethimes this connection is faulty...I know, I had to bypass the connector to make my gauge work.
Hope this helps

 

[Incorrigible]

Re: temp guage not working

Wouldn't be looking to the thermostat just yet either. The above steps are spot on. If you still don't have a working gauge, visually verify or test the wires between the sending unit and the gauge to make sure the signal makes it from the sender to the gauge

 

[Reming870]

Re: temp guage not working

The wire and the sender have nothing to do with the thermostat. They are independant devices. The sender only changes resistance as the water temperature changes. scv76 gives a good procedure above on how to check this. You can also try to bypass the wire on your own without a meter by running a seperate wire from the gauge to the sender and seeing if that works. The ohm meter is the best way to determine the problem.

If someone on here has a temp/resistance chart for the sender it would also be helpful and you could just purchase a resistor set for the temperature of 160-degrees and see if the gauge moves.

 

[imraan47]

Re: temp guage not working

The wire should not be grounded, it should only contact the stud on the sender unit. The sender unit is grounded via the threads where it screws into the manifold.
If you have and know how to use an ohm meter, disconnect the wire from the sender unit and connect your ohm meter between the stud and a good ground point. With water going through the sterndrive start the engine and watch the resistance change (goes lower) as the engine warms up.
You can also use the ohm meter (will need an extension wire to do this) to measure from the disconnected wire (the one you took off the sender unit) to the point where it goes to the dash gauge. This measurement should have almost no resistance. The wire from the sender unit goes through the main wiring harness connector, and somethimes this connection is faulty...I know, I had to bypass the connector to make my gauge work.
Hope this helps

when i said grounded i really meant that the wire has the eye and its making good contact with the stud. inf act there is a rubber waster before the wire eye goes in then a washer then the nut so i know its good to go.
Thanks for the detail. i will do this and see what happens. i dont have access to water outlet but i will do everything else and post back soon
i took the thermostat out to see it but its all rusty so i bought some rust cleaner and i will clean it up and put it back on there.

 

[scv76]

Re: temp guage not working

The wire and the sender have nothing to do with the thermostat. They are independant devices. The sender only changes resistance as the water temperature changes. scv76 gives a good procedure above on how to check this. You can also try to bypass the wire on your own without a meter by running a seperate wire from the gauge to the sender and seeing if that works. The ohm meter is the best way to determine the problem.

If someone on here has a temp/resistance chart for the sender it would also be helpful and you could just purchase a resistor set for the temperature of 160-degrees and see if the gauge moves.

I have this information, but I am at work and can not access it at this time. Will post some info tonight.
Do we think the resistance values at any given temperature of all sending units would be the same?

 

[Don S]

Re: temp guage not working

 

[imraan47]

Re: temp guage not working

ok so retested some things:

guage:
when you use a wire to hook G and S up it will only go to max when ignition is off. otherwise it wont move.

wire:
using ohm meter, one lead to S on guage and other lead to the wire that goes on the stud (wire unpluged. the meter goes to 0

i am not sure how to take sender out even so i need to find how to do that in order to follow Don S post

 

[Don S]

Re: temp guage not working

when you use a wire to hook G and S up

No one said you hook G and S together to test. To test, with the key in run position, you remove the wire from the sender and touch the wire to a good clean ground. Then the gauge should peg out.

using ohm meter, one lead to S on guage and other lead to the wire that goes on the stud (wire unpluged. the meter goes to 0

It should.

i am not sure how to take sender out

I'm sorry, but after re-reading your other replies, and if you can't figure out how to remove a temp sender, then you need to find a qualified tech to work on your engine.

 

[imraan47]

Re: temp guage not working

I'm sorry, but after re-reading your other replies, and if you can't figure out how to remove a temp sender, then you need to find a qualified tech to work on your engine.

i know how..its just that i have done something before then end up messing up and having to pay for it so when it comes to the boat i like to look up something if i have the smallest doubt.
anyway taking it to the lake so i will run this test there and post tomorrow night.

oh also i was just checking if guage is working or thats my problem so just to test guage it should move if G and S are hooked.

So to clarify i will remove wire to sender...hook ohm meter to that and the other lead to good ground and run engine. the meter should go lower in numbers so i guess i might see negative numbers. i will post back what the results of this is.

 

[imraan47]

Re: temp guage not working

i know how..its just that i have done something before then end up messing up and having to pay for it so when it comes to the boat i like to look up something if i have the smallest doubt.
anyway taking it to the lake so i will run this test there and post tomorrow night.

oh also i was just checking if guage is working or thats my problem so just to test guage it should move if G and S are hooked.

So to clarify i will remove wire to sender...hook ohm meter to that and the other lead to good ground and run engine. the meter should go lower in numbers so i guess i might see negative numbers. i will post back what the results of this is.

got myself a new thermostat for 24.80 and also got a temp sender
will install tomorrow and test at the lake..

 

[RayNMesa]

Re: temp guage not working

Is it just me or is every one shaking there head in disbelief ? :facepalm:

http://www.tpub.com/content/firetrucksandequipment/TM-5-4210-230-14P-1/css/TM-5-4210-230-14P-1_924.htm

 

[Outsider]

Re: temp guage not working

Mechanics just love folks who do their own work when they shouldn't. They call 'em job security ...

 

[imraan47]

Re: temp guage not working

Mechanics just love folks who do their own work when they shouldn't. They call 'em job security ...

can't beat $24.99 for a sender and thermstat.
installed it and well guage still wont go up.
so something in the wiring i guess. any ideas?