Sending units
 

Not sure of the year of the gauges and of course with the confusion of two Gaffrig companies I dont know which I have or which to call for assistance. I'd really like to just pick one up locally without having to call and wait/ pay for shipping on such a cheap part. So how do I get the correct sender for a Gaffrig water temp gauge? I only want one to eliminate an incorrect sender being a problem with a possible cooling issue I'm trying to resolve.

https://cimg9.ibsrv.net/gimg/www.off...b8d852aaf6.jpg
look around the outside edge of the gauges face...you would have to look under the rim of the gauge to see it...but the livorsi stuff will be labeled as such. or the older ones may even be labeled as autometer....should be able to narrow it down from there. :)

Even if I determine which gauge it is I still need to know what sender. Hoping to just pick one up locally. The issue I'm having is temperature extremes. When the engine is just warm I don't get a reading. When the engine is hot the gauge rapidly gets to 200. There's no in between. Trying to figure out if I possibly have the wrong senders. I don't really want to call the company and try to get them to tell me the specifics of the sender so I can get it locally. I also dont want to pay for a sender and for shipping and wait a week to just do a simple test on a cheap part. I have an ohm meter to test my current senders but not sure what reading I should get for these gauges to work. Figured buying what I know to be the correct sender would be easier than messing with an ohm meter at various temps. My guess is the gauges are from the 90's and since they are still good probably from the original Gaffrig when they were a known good product? I'll check the face later today.

are there no numbers on the sender ?

I will look at it closer in a couple hrs. If there are numbers it would tell me what I don't want to buy, not sure how many options that leaves.

bc,
I would go down to the local parts store and buy a cheap mechanical gauge for $20 Run it out through the engine cover and have somebody watch it for you while you run the boat. That way you will eliminate the wiring and power source as a possible issue too.

Post a pic of the gauge. I had a similar issue with one of my Gaffrig/Livorsi water temp gauges. It was a bad gauge.

Gaffrig Precision Instruments is now Livorsi
Gaffrig Performance is the current Gaffrig.

GSOT1/8

https://www.cpperformance.com/p-1307...si-gauges.aspx

that would be my guess. maybe you can find what the ohms are somewhere

Payupchump might be right thou. Maybe it`s a warning sender

Actually this one is probably the correct one: https://www.cpperformance.com/p-1307...si-gauges.aspx

Not sure what the OP is running but on my engs, on the thermostat housing, there's a temp switch and a temp sender. They look very similar and the connection is the same type (ring terminal on a post with a nut). The temp switch actuates the warn horn if temp gets to high.

This whole thing started because of the engines inability to build any heat in the oil or water despite having thermostats in both systems (water has a crossover with bypass and stat which I know some people dislike because of these problems, but I'm trying to learn exactly why some work and some don't before abandoning the setup). I initially thought it would just be a matter of selecting the correct t-stat to get some water temp, so I went out with 3 different stats to get some temp readings and couldn't get the gauge to even move. The gauge starts at 100° so I was either under 100 or there was a gauge / sender problem. Just for the hell of it I decided to run without the t-stat to see what would happen. In the few minutes it took to get the boat on plane and trimmed out the temp gauge was at 200°. I could tell by touching the engine that it was definitely hotter but this seems a bit extreme to go from <100 with a stat to >200 without one in a couple mins. This is why I was looking to rule out the sender as a problem. After going out again today with a temp probe I'm inclined to believe the sender is correct and those are the actual temps.
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- if anyone has any thoughts on why I can only get 80° with a stat but hit 200° without one and nothing in between I'd like to know.
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As far as the sending units go, it would still be nice to figure out exactly what the correct one is for this type gauge in a non marine application so it can be purchased locally and not have to go mail order through CP.
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Griff, all the electric gauges say Gaffrig Precision Instruments. All the mechanical gauges just say Gaffrig which I thought was interesting that they were labeled differently.

https://cimg4.ibsrv.net/gimg/www.off...616e36e33f.jpg

Sorry about the terrible photo but battery was too low for flash so i had to try shining a flashlight on it.
https://cimg5.ibsrv.net/gimg/www.off...a78f24eb3f.jpg

This is the t-stat housing which has a diverter in it so bypass water doesn't go right on the thermostat. In theory...

What if there is not such a thing ? If I was having a problem I would want to make sure I had the correct sending unit. You would have already had it by now if you ordered it from CP.

I ruled out the sending unit last time out by using a separate device to read temps. My gauge readings are correct, I'm under 90° with a stat and at 200° very quickly without one. I didnt want to order one from CP because yesterday was the last run for the year to burn the fuel out of the boat for the winter so I figured I'd use it to do some testing as the boat was only out a few times all year and even in the warmer temps it wasn't building heat but I just didnt have the opportunity to look into it. I was looking to get a sender in the morning and use it the same day thinking that would be easier than opening hatches and manually checking temps multiple times. I don't believe Gaffrig developed a proprietary sender just to use in their gauges but of course I might be wrong.

Those are similar to my gauges, except the position of the numbers. Mine use a stock Merc sender. If you look at mine, you will see my 165* position is the same as your 200* location. So, yes I do think you probably have the wrong sender for your gauge. If you pull the gauge it should have a sticker on the side that tells you what ohm sender it needs.
https://cimg8.ibsrv.net/gimg/www.off...109f6804d6.jpg

If you go to the Industrial Series gauges, the 100-250* gauge has the same layout as yours and it should use the same sender. http://www.livorsi.com/pdf/lmi%20volume%2018_rev5.pdf

I'll pull the gauge and see if I can find the sticker you mention. Thanks for the info.

When I wanted to verify temps I`d boil some water on the stove let it cool a bit , put in a $5 thermometer and the sender and see if they read the same

Yeah, that's the plan for the winter. I'll check the resistance through the sender at the same time to help identify it if necessary. I've got 6 or 7 months now.