Anyone familiar with these marine gauges?

[triply]

I have a complete set to install in my boat. I’m replacing all of them just for a new look, but am having issues with the trim gauge.

My boat is powered by Mercruiser and the gauge is for Mercruiser application.

My old gauge works perfectly fine, but this new one has an extremely sloooow needle response time. You have to wait for the needle pointer to play catch-up with the actual position of the outdrive.

Not happy with how it’s working.

Just wondering if any of you have these in your boat and how they are working for you.

 

[Chris1956]

Trim gauges are pretty unreliable in my experience. I never had one that read consistently. Part of it is that the rheostat that controls them is exposed to the water, causing corrosion.

A far better way is to trim by sound and feel of the boat. The trim gauge can be useful when tilting the outdrive all the way up for trailering.

 

[Texasmark]

Are you using a "furnished with the gauge" sending unit or are you using your original? If you have a resistive circuit tied across 12v and ample current capacity via the size of the wiring used, with "clean and tight connections, including wiring crimps and clean bayonet type plugs if used, no reason for any delay. In a purely resistive circuit V=IR and the changing of the resistance in the outdrive proportionally changes the resistance in the meter circuit, without delay, and changes the deflection due to more or less current flowing, unlike an AC circuit where inductive and capacitive reactances are involved. Where is the mechanism for sluggishness?

In trouble shooting, you might look for potential problems Chris mentioned.
Then disconnect the sending unit and measure across the contacts with your ohm meter while moving the outdrive up and down. When you stop moving the outdrive ensure that the resistance reading does not continue to change.....aka lagging the movement.

Then, reconnect the wiring and go to the gauge and disconnect the sense signal and meter ground (battery -). Ensure that you get the same readings as before, within a few Ohms allowing for a slight increase in resistance for the wiring drop.

Then, reconnect the wiring and with your voltmeter, get back on the same signal-ground contacts with your voltmeter expecting to see voltage changes from low to high in the range of 0 to 12v as you move the tilting of the outdrive and when you stop movement the voltage change should stop immediately. If it doesn't. check the 12v supply voltage across the meter while you are moving the outdrive and ensure that it is steady and not dipping down when you move the outdrive...if it does, replace the wiring or install new contacts/terminals.

If all that fails, I'd pack it up and send it back to the seller.

 

[Blind Date]

Looks like your not the 1st person to have this issue with an Autometer trim gage unless your the same guy who asked this question 15 days ago. See below:


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SS-C · 15 days ago
I have trim gauge 200766-40 that will not work properly with my Mercruiser Bravo outdrive. My old gauge (Faira) works perfectly, but the new gauge not so, the needle movement is very much delayed, it does not read in real time. Is there a quick fix?
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Jim from AutoMeter · 15 days ago
Hi SS-C, Please call our Tech Support Team at 866-248-6357 for assistance with your Trim Gaige. Thanks, Jim

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Jonas · 2 years ago
Can I use this guage whit mercruiser trimsender? Thanks in advance
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Joseph At AutoMeter · 2 years ago
Hi Jonas, thank you so much for contacting us. This gauge should work with any 0-90 ohm trim sender. I believe that's the range used on the Mercruisers. Hope this helps!

 

[Scott Danforth]

remember, the trim gauge is no different than a fuel gauge or a temperature gauge.

variable resistance to ground is all that the sender is. that in turn applies voltage to the air-core motor and makes the gauge move

in fact, most of the gauges use the exact same air-core motor and just a different set of resistors on the inside.

90% of the time, the issue is in the wiring or the sender.

 

[ahicks]

Just an idea, but wondering if the issue isn't related to the "damping" built into most instruments to keep them from jumping all over?

If the gauge is eventually settling down where it should, there's nothing wrong with the sender (unless that's what's sticking?) or the gauge calibration, it's just a too "draggy" gauge.

 

[triply]

Wow,

Thanks for the responses guys!

From what I’ve learned so far, and what I’ve been told, the new gauge and my sending unit are not compatible with each other.

Apparently there is some discrepancy between the gauge manufacturer and Mercury. Mercury Marine tells me that my Mercruiser is equipped with a 0-160 ohm sending unit. The original factory installed trim gauge would have to meet those same ohm values in order to operate correctly, which by the way it does.

So far, this all makes perfect sense because I have checked the ohm value of my sending unit which reads 10.6 - 159.8 ohm. With the adjustment screw removed, it goes as low as 1.4 ohm.

The Autometer people however, tell me that Mercury’s 2 wire trim sender is 0-90 ohm, and all their trim gauges are made with the 0-90 ohm spec. only.

Ok, yes, this is and has been confusing for me, but now I do know my trim sender is in fact 0-160 ohm as the people at Mercury Marine said it would be. And yes, it too is a 2 wire!

So, what’s going on here? Well, I’m not really sure, but I certainly would like to find out.

 

[Texasmark]

A 2 wire resistor is called a Rheostat. It consists of a wire attached to a resistive element that is 0 or some minimum value to protect the displaying instrument if needed, to some higher resistive value at the other end. The second wire is attached to a moveable wiper that is positioned by the mechanical movement of a surface to which it is attached and as it moves along the resistive element, it changes resistance, which changes the current through the displaying instrument and changes the deflection position of the needle.

Fuel gauges are wired as such and also have to be matched, and usually have a minimum resistance of like 35 Ohms with max of 160 or something of the sort . What you need to have happen, is that the resistance of the Rheostat (resistance value as a function of wiper position) has to provide the correct current to the meter so that the position of the wiper and needle on the gauge correspond to the correct value. Having too much or too little resistance in the Rheostat for a given gauge results in display errors.

If all else fails, you could calibrate your gauge to your engine's position with what you have. Just get a protractor ($ General sells plastic ones) and measure the angle of the engine, making a column for that and a corresponding column for the dash gauge needle position. Put the chart where it's handy and go for it.

On gauge dampers, usage is normally for pulsating conditions making for needles vibrating at high speed and the damping mechanism is filling the gauge with light mineral oil. Your trim gauge is not of the type to require damping.

 

[Scott Danforth]

they make gauge sender converters

like these
https://www.speedwaymotors.com/Speedway-Fuel-Level-Gauge-Sending-Unit-Interface-Module,66534.html
https://www.ebay.com/i/262975817155

used by hot-rodders doing engine swaps.

In this case like converting a VDO 10-180 ohm sender to a 0-90 ohm gauge