temperature gauge question.

[stevea661]

My 1986 268 da gauge reads about 185, on the muffs when warmed up, I have a closed cooling system through the manifolds. the boat is new to me. I have never had it out. The engine is new, I just fired it up last week. The fresh water cooling is new, I installed it when I installed the engine. The engine and drive system is omc. The alternator is overcharging the batteries to about 16.75 volts so I have a new alternator comming. The temp sensor reads off a tee in the water heater loop When I read the brass tee with my temp gun it reads about 165 degrees, the thermostat in the system is 160 degrees. The way I understand is that the gauge gets the signal from the sender, and that it is the positive side is a constant of whatever the battery voltage is on the positive side. The sender sends variable ground back to the gauge, more for higher temp and less for lower temp. Resistance drops as the temp rises
I have already changed the sender and the results are the same. The question I have is this, when I install the new alternator and the voltage goes down on the positive side will the reading on the temp gauge also go down and be closer to the actual temp of around 165? Or should I just order all new gauges because I can't find one that matches the existing ones. The old gauge is screwed up and a 2.5 volt drop won't make a differance:huh:

I took the alternater out of the loop and the temp on the guage dropped to 175. The question I have now will changing out the guages get me closer to the 165 degrees which is what the temp really is or is 10 degrees one way or the other considerd acceptable and I'm just being too frigin anal

 

[stevea661]

One of you guys have got to have an answer to this:smt089

 

[Lazy Daze]

I'd say just live with the gauge reading 10* higher. As long as you know (remember) that the actual is 10* lower, so what? You don't need a calculator for that, do you? :grin::lol:

 

[stevea661]

I'd say just live with the gauge reading 10* higher. As long as you know (remember) that the actual is 10* lower, so what? You don't need a calculator for that, do you? :grin::lol:

I'm just a plumber dam it not a scientest:huh:. But really do you think the 10* differental holds true througout the range? I just put a new engine amongst a plethera (big word for a plumber, huh) other things into and onto the never ending project and don't look foward to doing it again any time soon.

 

[Lazy Daze]

I don't know. I guess you could try it - use your thermometer as it's warming up. However, the only thing to be worried 'bout is the final temp, you know? Save your money. There's no guarantee that a replacement gauge is going to be spot-on, either. If it consistently reads the same temp, that's good enough. Bring your thermo with you on your first few trips - check the temp once in a while - you'll probably find you'll be happy with it.

 

[stevea661]

I installed all new teleflex gauges today. Now the temp gauge runs within a few degrees of the temp gun. :smt038 The new gauges look cool too. The only hard part of the changeout was that the connection to the dash lighting on the gauges changed from a ring type terminal to a spade type so those connectors had to be replaced. Everything else just reconnected. Teleflex hasn't changed much since 1986:smt001

 

[Lazy Daze]

So you bit the bullet and did it all, huh? :smt001

Not for nothing, but you know, you could of just snipped the center portion of the ring terminal off to make a spade...

Oh well, glad it's all working for you!

 

[stevea661]

So you bit the bullet and did it all, huh? :smt001

Not for nothing, but you know, you could of just snipped the center portion of the ring terminal off to make a spade...

Oh well, glad it's all working for you!

Thanks. I seem to be a profesional bullet biter since I've owned this boat:smt021