Hey all,

I’m in the process of replacing all my gauges with the Autometer marine gauges. My existing gauge cluster consists of Faria which all presently work perfectly. I’m only replacing them to upgrade the looks of my dash. Well, with all gauges in hand, I started with the trim gauge as it was supposed to be a direct replacement for Mercruiser. The install was simple, basically just 3 terminal connections that matched the existing Faria. Once installed, I checked it out with the boat on the trailer. To my surprise, the gauge didn’t act like the Faria, the needle pointer moved very slowly and I mean at snail pace. You literally have to wait for the gauge to play catch-up with the actual real position of the outdrive. Ok, I must have done something wrong, right? I went back and rechecked everything I did, it all looked fine and so I tried it again with the same results. I spent hours messing around trying to figure this out. I cleaned all wire terminals, ground connections, fuses etc, even put the old gauge back in just to make sure everything was good. I gave up and decided to call Autometer for help. The seasoned gauge tech (32 years with Autometer) I spoke with was not of much help. He said he has never encountered anyone having this particular issue with their Pro-Comp trim gauge & Mercruiser. He also said maybe Mercruiser changed the ohm rating of their sending units and if so, this gauge will never work. He said all their trim gauges require 0-90 ohm to work properly, if my sending unit is anything other than that it will not work and there was nothing he could do to help me with that.

So, my question to you all here at OSO is, how many of you are running the Atometer Pro-Comp marine trim gauge and how is it working for you?

Thanks in advance.

I have the pro-comp trim gauge and it works well and consistent with the old Faria that I replaced 5 years ago. You may want to send yours to Autometer and have it checked. I have had great luck with customer support from them as well, sorry to hear that you haven’t. Have you put a meter on the input wires as you raise the drive?

Yes, multiple times. My readings are trim fully down 10.6 ohm, fully up 159.8.

To confirm whether or not these ohm values are correct I called Mercury Marine headquarters to find out about my trim sending unit. I had a nice 30 min chat with Bill regarding my issue and he gave me some good information. I gave him my engine/drive serial number and with that he was able to confirm the Mercruiser sending unit specifications/ohm range is correct.

He said your Autometer gauge with the 0-90 ohm will not read correctly. The needle will overshoot the parameter of the markings on the gauge face and possibly the reason for the slow reacting time.

ph1971, just curious, are you powered by Mercruiser as well?

Yes, I have a mercruiser Magnum transom assembly that was new in 2018. The unit was assembled with trim sender and limiter in place and they appear to be identical to my old Bravo senders. In both cases I adjusted the sender to put the gauge needle on the lowest mark with the drive in the fully down position. With that done the gauge reads just under half way when the drive is raised to the limiter. When I continue to raise the foot with the trailer button the gauge is buried before the drive is all the way to the top, but that has never concerned me because up is up and that means it’s on the trailer. If the parameters are off between sender and gauge, I’ve grown accustomed to it. I’m sure none of this info helps you understand why your needle moves so slow.

Hi ph1971,

Thanks very much for sharing this info with me, and yes, mine is doing that same thing too, but slowly.

Yes, it gives you a false reading and when the needle is pointing to the “up” position on these gauges, up is NOT up, your prop is still hanging down!

This is not just an adjustment issue either, it is the fact the gauge and the sending unit are not compatible to work with one another.

I’m not ok with this as you are, I believe a gauge should give a very accurate account of what’s going on in real time, no matter what type gauge. Otherwise what good are they? No reason to have a gauge read incorrectly.

It actually does now since this new post you made, your previous post made it sound as though the gauge was working fine without issue.


I now know this statement is not possible, the ohm values confirm this. The Pro-Comp Autometer gauge will never read consistent with the Faria/Mercruiser combination.

The needle pointer being laggy is a phenomenon due to the mismatch in ohm values, probably just something you never really paid much attention to.

The fact this gauge is “for Mercury/Mercruiser” and marketed as such is just plain WRONG!

I’m sure you bought this gauge under the same pretense, thinking it was for Mercruiser.

Makes me wonder how many others have done the same.

Well, I have been working on this problem off and on for 4 months now. I have once again contacted (via email) Autometer about the issue, but this time someone higher up in management. I again explained the problem and he told me they only make one trim gauge (0-90 ohm) and that Mercury has traditionally used a 0-90 ohm sender for many years. He insisted that the problem is on my end. I again explained to him my old Faria gauges work perfectly fine, that I had to put the old one back in so I have a fully functioning trim gauge, only reason for the change is to up-grade the look of my dash. His response back was that my trim sender must be bad, or I have the wrong one installed. I emailed him back and shared the information I received from Bill at Mercury Marine about my 0-160 ohm sender being correct and asked him if it was at all possible the information/documentation they have with respect to their ohm values could be wrong?

Guess what, never heard back from them again.

This is still unresolved; I believe these trim gauges are being misrepresented and, or Autometer is producing gauges of the wrong ohm value for a direct replacement for Mercury / Mercruiser.

Any suggestions on how to resolve this issue?

Did you find a solution for this?
I have the exact same problem but my new gauge doesn't move at all. New transom with new trim limit/sender aswell.
This is 3 years later and why wont they write on their website that its not compatible with mercruiser trim units???
I spent almost 2000 dollars on my gauges and now i have 1 that doesn't work