Impossible trouble with dual temp gauges

[bwindrope]

I've been having an impossible time trying to get two separate temperature gauges to work, and you would not believe the headache of it all. First off, I have a pilothouse, and so with two wheel stations, I need and want dual stations for temp and tach. I have installed all the hardware, but have been trying for about 6 months to get the gauges to work.

Before anyone jumps to conclusions, I know I need a dual station sender, and that has been the problem. I've also checked the actual engine temperature with independent means and it is normal at a coolish 165. I've been on the phone with Teleflex tech support to no avail. I have the proper identical gauges, all the wiring is perfect, and works fine with my old single station sender when they are hooked up one at a time. So I have narrowed the problem down to the sender itself.

Turns out Teleflex doesn't make a 1/4" dual station sender. There went 5 months of effort with Cook Engine in Portland, Oregon sending me and then resending me the wrong temperature senders. Holy moses Finally, after hours of my own research online, I found out that Sierra Marine, an offshoot of Teleflex, makes the proper sender. So I order it, it comes today, and I install it, and they still doesn't come up to temperature!!!!!!!!!!!

Most things take patience, but this is ridiculous. Power boats across the land have dual stations, and I can't get this simple installation to work.

To recap:
Gauges new and identical and suited to dual station use.
Gauges work properly when connected to a single station sender and come up to the accurate 165 degrees.
When connected to the purported proper sender (TS26651)they do not rise above a reading of 120 degrees.

I'm defeated, and furious, and flabbergasted. and any help whatsoever that solves this problem will earn my profound appreciation.

[Hartley18]

This might sound like a stupid suggestion, but for the price of these things (10 bucks) and the effort you've put in, why don't you simply install two senders in the same line??

This has the added advantage that if one goes kaput for any reason, the other gauge should still work..

[bwindrope]

Hartley18,
I'll do that in a heartbeat if I can figure out how! My motor is a Universal M40 and the sender is screwed into the housing that holds the thermostat down. There is only the one threaded hole. I've tried to imagine some other place or way to install a second single station sender, but haven't hit upon an idea.

If you know of some way, I'd be way too happy. When you say install another in the "line", what do you mean by "line"? Thanks for the idea.

[jrd22]

You could use a short piece of 1/4" pipe and a "T" that you could screw the two senders into. I don't like the extra fittings and hanging the senders on a small piece of pipe that will have a great deal of vibration though. Isn't there another threaded fitting into the water jacket somewhere, a block drain or something you could use even if you had to use a bushing?

John

[Faster]

Unfortunately taking a sender tap away from the thermostat housing is likely to create a dead zone that will not reflect the proper temperature anyway. Unlike pressure, which could be tapped off, adding even an inch of pipe and fittings will take the sender out of the flow path, and the sample will cool and not be representative anymore.

Sounds to me like you still have sender issues unless the wiring is perhaps not quite perfect after all.

[Hartley18]

It really does sound like a sender issue. Is there anywhere on the jacket you could drill and tap another fitting?

(Apologies, but I'm not familiar with Universal motors and can only guess at the jacket configuration)

[timebandit]

Do the gauges have one or two wires?
If two wires could the wires be reversed on one gauge ?

[sailaway21]

WHOA!

I just re-read your post for the third time. You say that the new guages will not rise above 120 degrees. Does that mean that they are registering, just not accurately? Because I think everybody here is assuming they're not registering at all. If that is the case, you probably need guages to go with your new sending unit that is designed to provide a certain resistence that triggers a specific guage a certain amount. Not all electrical guages are designed to work with all sending units.

[jrd22]

Faster- good point, they would register a lower temp than in the coolant flow which is not good. I don't like things "hanging" on threaded pipe on the engine anyway. Seems like there must be another place to tap into the water jacket.

John

[christyleigh]

Originally Posted by bwindrope

To recap: Gauges new and identical and suited to dual station use.
Gauges work properly when connected to a single station sender and come up to the accurate 165 degrees.
When connected to the purported proper sender (TS26651)they do not rise above a reading of 120 degrees.

I added a second Tach, Temp, and Oil Press a couple years ago to my cockpit so I feel some of your pain. As someone mentioned - have you tried wiring both gauges to the Single sending (in parallel) unit just to see what numbers you come up with ? At this 'grasping at straws' time I'd be trying things like that if only to see if the result is similar to the Dual Sending unit - if so then the 'Dual' Sender may be the problem. My guages are VDO and the original on my '99 are out of production so I had to jump through a few hoops and a lot of research to order new ones - one being to be sure of the match of the 2 flavors of guage (as someone else also mentioned) - one that reads higher with more resistance and the other that reads lower with more resistance, etc.....
To add to another poster's comments about vibration.... I had to stack multiple Oil Press sending units and although it didn't vibrate off by itself it was ready to fail when I 'bumped' it off. I ended up running an 18 inch hose out of the block to an area where it could be secured to 'gang' my multiple senders - 3 in total because of the want/need of a cockpit beeper/light that couldn't be wired in with the guage.
Our situations are different but I just thought I'd throw out some comments. Good Luck