Water Temp Gauge - I/O vs. Outboard

[convergent]

I think my water temp gauge is bad and the one I'm looking at (Teleflex Eclipse) comes in either an I/O or Outboard variety. Every place seems to have the I/O version but not the Outboard version. This is probably a stupid question, but are they really different, different senders, or can they be interchanged?

 

[Silvertip]

Re: Water Temp Gauge - I/O vs. Outboard

That depends on how the gauges are calibrated. Some don't have numbers but simply read "C-N-H" (cold, normal, hot). If you are comparing an I/O and an outboard gauge and both scales are the same at the top and bottom end then the sender for either of those gauges will work. Outboards and I/Os tend to run at different temperatures with outboards being cooler than I/Os. So yes, there is a difference. The sender must always match the gauge. Outboard senders are typically 33 - 240 ohms resistance.

Now the real question! What makes you think the gauge is bad? Test it by grounding the "S" terminal to ground with the key on. It should peg high. Gauges are rarely the problem. Wiring and senders are #1 and #2 respectively. If the gauge checks ok then check the sender using a pan of water, an ohm meter, and a meat/candy thermometer to monitor temperature. Plot the resistance.

NEVER start replacing parts unless you KNOW they are bad.

 

[convergent]

Re: Water Temp Gauge - I/O vs. Outboard

Thanks Silvertip. I already tested the gauge a while ago. I had another thread where I had two gauges... trim and temp... that were both dead and I suspected something in the wiring. But all that stuff was fine. I already replaced the trim gauge and its working great now. The local Overtons didn't have any outboard gauges in the design I was looking for. Oddly their computer system showed two in stock, but we couldn't find even a place on the shelf marked for it, so something was amiss. The gauges I'm looking at do have actually tempertures on them, and not L-H, so I guess it makes a difference. The gauge I'm replacing does have L-H though.

 

[convergent]

Re: Water Temp Gauge - I/O vs. Outboard

I finally just ordered a new gauge, and even though all the online pictures of this gauge had it looking very similar to the inboard and I/O gauge (with actual numeric temperatures), what I received just has L and H and actually says Outboard Temp on the gauge itself instead of Water Temp like the other one. So it is just like the one it replaced and now is working fine.

If anyone is looking for replacement gauges that are black with a black ring around them (not chrome), and have white and light blue markings, and have a "Q" logo on them, this series seems to be a direct placement and looks at home in the dash with them. I am guessing the "Q" is Quicksilver and that the factory gauges are from Mercury, but I'm not positive of that. I just know that the Teleflex Eclipse series is a great replacement product for them. You'd never notice the difference by casual glance at the gauge, and the wiring on the back of the gauge is identical.

I'm thinking of replacing the Speedometer now because the one I have is not very accurate and starts moving only around 20-25 mph and goes well beyond what the boat can do. This series has a 65mph gauge that starts with scaled lines at 10mph and the boat won't go over that speed.