Water Temp Gauge Replacement

[Captain K]

My 1978 Marine Trader Trawler with twin Lehman 120's needs new water temperature gauges. Only one of the original four is still working. Anybody know where I can find replacements for the original "AC" units (fit 52mm hole, bezel size about 58mm)? If not, any suggestions on suitable alternative replacements? Thanks.

 

[FF]

My recommendation is always to install Murphy Gauges.

They have an adjustable alarm function and are mechanical, so will operate at all times.

If other folks take the helm at times having an alarm for as many functions as can be done is a great safety insurance policy.

 

[jleonard]

I replaced my gages and sender with VDO. They are very accurate when compared to readings on an IR gun. I bought them via egauges.com

 

[Captain K]

Thanks gents. I think I've found what I need. Called American Diesel. They're shipping new gauges and senders. I appreciate your help!

 

[River Cruiser]

Thanks gents. I think I've found what I need. Called American Diesel. They're shipping new gauges and senders. I appreciate your help!

Did you test the circuits to determine where the problem is? With the key on if you ground the wire on the sender & the gauge pegs the gauge & wiring are good & the sender is the problem. If the gauge doesn't peg then the gauge or wiring is bad, to find which is bad ground the stud on the gauge that the sender wire attaches to if the gauge pegs the wiring is shorted, if it still fails to peg the gauge is bad. Good luck

 

[sea hag]

Did you test the circuits to determine where the problem is? With the key on if you ground the wire on the sender & the gauge pegs the gauge & wiring are good & the sender is the problem. If the gauge doesn't peg then the gauge or wiring is bad, to find which is bad ground the stud on the gauge that the sender wire attaches to if the gauge pegs the wiring is shorted, if it still fails to peg the gauge is bad. Good luck

River Cruiser

Does this test method work with all mechanical gauges with sending unit ! Fuel, water, etc ?

Thanks.

 

[RT Firefly]

Greetings,
I think this technique will work with all ELECTRICAL gauges except the tachometer.

 

[FF]

For a mechanical gauge just plunk the bulb in a pot of boiling water , should show 212F if you are at sea level.

 

[Captain K]

Did you test the circuits to determine where the problem is? With the key on if you ground the wire on the sender & the gauge pegs the gauge & wiring are good & the sender is the problem. If the gauge doesn't peg then the gauge or wiring is bad, to find which is bad ground the stud on the gauge that the sender wire attaches to if the gauge pegs the wiring is shorted, if it still fails to peg the gauge is bad. Good luck

I'm afraid the answer is no. Wish I'd had your very valuable information before I ordered the new gauges and senders from American Diesels, but I suspect I'd have to order new stuff anyway. Here's why: I have two helm stations and two engines. The lower helm station water temp gauges have been inoperative since I bought the boat 3 years ago. Both the upper helm station's gauges worked A-OK. Then this past weekend, the port engine gauge at the upper helm failed, the needle pegged on the high side at 220-F. As a precaution I shut down the port engine until I could get back to my slip and trouble shoot the problem. Once home, I switched gauges at the upper helm. I discovered then that the port gauge worked fine, while the former port gauge (now on the starboard side) gave the same faulty indication before the switch. My conclusion, perhaps incorrect, is: (1) the senders must be good, otherwise the upper helm gauges would not have been working just fine until now, and (2) the wiring must be good for the same reason. I'd very much appreciate your thoughts and comments on the above.

 

[RT Firefly]

Greetings,
As with anything, working fine up until now doesn't mean working in the next two minutes. ANY time I have an electrical problem the first thing I check is the wiring. Power source first then grounds. A VOM (can be had for $5) Digital Multimeter - 7 Function, w/ Backlight
Corroded connections or bad splices are common on a boat particularly if the PO was a "Rocket Scientist" or of the "out of sight-out of mind" school of maintenance.
You will still be further ahead by changing your gauges. Now you should have working gauges at BOTH helms and that's a good thing.

 

[River Cruiser]

I'm afraid the answer is no. Wish I'd had your very valuable information before I ordered the new gauges and senders from American Diesels, but I suspect I'd have to order new stuff anyway. Here's why: I have two helm stations and two engines. The lower helm station water temp gauges have been inoperative since I bought the boat 3 years ago. Both the upper helm station's gauges worked A-OK. Then this past weekend, the port engine gauge at the upper helm failed, the needle pegged on the high side at 220-F. As a precaution I shut down the port engine until I could get back to my slip and trouble shoot the problem. Once home, I switched gauges at the upper helm. I discovered then that the port gauge worked fine, while the former port gauge (now on the starboard side) gave the same faulty indication before the switch. My conclusion, perhaps incorrect, is: (1) the senders must be good, otherwise the upper helm gauges would not have been working just fine until now, and (2) the wiring must be good for the same reason. I'd very much appreciate your thoughts and comments on the above.

I would guess you are correct, switching the gauges seem to indicate that you are. Are your senders for duel station gauges? The reason I ask is that usually 1 sender will feed 2 gauges & if the lower helm temp gauges didn't work & the ones on the FB did then most likely the lower helm gauges or wiring is faulty. Many owners will think they're a genuine electrician & mess with 12v but would never do the same with AC, I've been helping on a boat that that has had to many owners like that & the DC circuits are a mess. If I ever buy another boat the 1st thing I'll check is the wiring if its been hacked on or there are any electrical gremlins in the systems I'll walk away right then.

 

[Captain K]

I would guess you are correct, switching the gauges seem to indicate that you are. Are your senders for duel station gauges? The reason I ask is that usually 1 sender will feed 2 gauges & if the lower helm temp gauges didn't work & the ones on the FB did then most likely the lower helm gauges or wiring is faulty. Many owners will think they're a genuine electrician & mess with 12v but would never do the same with AC, I've been helping on a boat that that has had to many owners like that & the DC circuits are a mess. If I ever buy another boat the 1st thing I'll check is the wiring if its been hacked on or there are any electrical gremlins in the systems I'll walk away right then.

Honestly, I do not know the answer to your question, but I assume the senders are for dual station gauges. Perhaps that ASSumption makes me an ASS? I concur with your resolution to check out the wiring in future!