Trim Gauge - up is down....down is up

[Shamfarlango]

I have twin OMC 3.8L with 800 series stringers with hydraulic selectrim.

My dash gauges are backwards, so up is down and vice versa. It was this way when I got the boat, workable, but now i've repaired most of the bigger things and am starting to pick away at the annoyances.

So...is it as simple as switching some wires on the back of the gauges to make up/up and down/down?

 

[dockwrecker]

Re: Trim Gauge - up is down....down is up

Well that certainly would be the easiest thing to try, makes sense to give it a run. If it's totally wrong you'll see the needle bury in the wrong direction. Worst case you take out a fuse but not likely.

 

[EricJRW]

Re: Trim Gauge - up is down....down is up

My understanding of a trim position senor is that is just a variable resistor that changes resistance based on position, as such there is no polarity. Some systems are low resistance for up, others are low resistance for down. Ohms can range from 1 (and not all start at 1) to 400, based on make, model and year. I'm no expert, but perhaps the sender and the gauge are mis-matched, or maybe the gauge can be configured for the type of sensor? My thought is that changing wires is not going to fix it, as there's no polarity when it comes to resistance. I'd dig into the gauge itself and see if it can be configured... At the very least report on the make of the gauge. That would be helpful (not to me, but for others).

Oh, and has it ever worked? If you are handy with an ohm meter, you can check the operation of the sending unit.

PS. Just came across this thread: http://forums.iboats.com/showthread.php?t=545065

There's a link to a PDF that will shed additional light.

 

[dockwrecker]

Re: Trim Gauge - up is down....down is up

My understanding of a trim position senor is that is just a variable resistor that changes resistance based on position, as such there is no polarity. Some systems are low resistance for up, others are low resistance for down. Ohms can range from 1 (and not all start at 1) to 400, based on make, model and year. I'm no expert, but perhaps the sender and the gauge are mis-matched, or maybe the gauge can be configured for the type of sensor? My thought is that changing wires is not going to fix it, as there's no polarity when it comes to resistance. I'd dig into the gauge itself and see if it can be configured... At the very least report on the make of the gauge. That would be helpful (not to me, but for others).

Oh, and has it ever worked? If you are handy with an ohm meter, you can check the operation of the sending unit.

Absolutely correct.^^^^ (but I'd still try it for grins...)

 

[bruceb58]

Re: Trim Gauge - up is down....down is up

Typically the senders have 3 wires on them. You only need to use 2 of them and you are using one of the wrong wires.

For example in this picture:

You may be hooked up to A and W where you really need to be hooked up to B and W.

 

[roscoe]

Re: Trim Gauge - up is down....down is up

I know absolutely nothing about how these work.
But wouldn't the easy fix be to rotate the gauge 180*.

 

[EricJRW]

Re: Trim Gauge - up is down....down is up

Bruce, are all senders like that? I don't know why, but I seem to recall it was one wire and the resistance to ground was used (or am I thinking of a different gauge)? If what you posted is correct, at least for the OP, then I stand corrected and there probably is a wire or two that can be reversed, though now I would be very careful not to send any power to the sender.

 

[bruceb58]

Re: Trim Gauge - up is down....down is up

Some are some aren't.

 

[EricJRW]

Re: Trim Gauge - up is down....down is up

Some are some aren't.

That's good to know (and that my brain is still working).

 

[Shamfarlango]

Re: Trim Gauge - up is down....down is up

Thanks for the info guys, i will take a look at the back when i go down to the boat tomorrow night and see how many wires it has. Also grab the make model.

As for did it ever work question: It does work, its just the opposite. So when i'm trimmed up the gauge says down and vice versa.
Wouldnt it be grand if I could simply switch the wires, but i'm not usually that lucky :facepalm:

 

[rfdfirecaptain]

Re: Trim Gauge - up is down....down is up

I just did some PM work and replaced my existing trim position sensor afterward. I noted the same thing, up was down and vice versa. I removed the trim position sensor and rotated the pin 180 degrees. It took all of 10 minutes and solved the problem.

Also, just an FYI in case you ever have this problem.... I got in a bind some years ago and couldn't get my outdrive up at the boat ramp. I had power going down but none going up. I called a marine mechanic friend and he told me to jump the wires over near the pump. I asked which wires. He told me it's simple. There is a green and a blue wire. Just remember Green is for grass (down) and Blue is for blue skies (up).

 

[EricJRW]

Re: Trim Gauge - up is down....down is up

I just did some PM work and replaced my existing trim position sensor afterward. I noted the same thing, up was down and vice versa. I removed the trim position sensor and rotated the pin 180 degrees. It took all of 10 minutes and solved the problem.

I know absolutely nothing about how these work.
But wouldn't the easy fix be to rotate the gauge 180*.

Looks like you might have called it!

Looking forward to see how this turns out.

 

[ezmobee]

Re: Trim Gauge - up is down....down is up

You've got a Merc gauge with an OMC. They're backwards. Ask me how I know this :facepalm:

 

[Shamfarlango]

Re: Trim Gauge - up is down....down is up

You've got a Merc gauge with an OMC. They're backwards. Ask me how I know this :facepalm:

Now I have to ask LOL

Did you replace the gauges or live with the silliness of up is down?

 

[Shamfarlango]

Re: Trim Gauge - up is down....down is up

Looks like you might have called it!

Looking forward to see how this turns out.

I have no idea what a trim sensor might look like on an 85 OMC Stringer 800. Where would someone start looking for one of these?
Assuming in the engine compartment somewhere?

My trim is hydraulic selectrim.

 

[EricJRW]

Re: Trim Gauge - up is down....down is up

Have you looked at the parts diagrams at http://shop.evinrude.com/ ?

I find the diagrams to be invaluable.

PS. If it helps, it looks like it's in the "Engine Mount Group" - I drilled down in "384STMRCOM 1985" (thinking ST might be Stringer) and found it... Part number 14. That should help locate the sender.

 

[ezmobee]

Re: Trim Gauge - up is down....down is up

Now I have to ask LOL

Did you replace the gauges or live with the silliness of up is down?

Currently living with the silliness. It's a multi-function gauge so thats just one of four functions.

 

[Shamfarlango]

Re: Trim Gauge - up is down....down is up

Currently living with the silliness. It's a multi-function gauge so thats just one of four functions.

Very funny, I suspect I will end up in that situation too. Damn OMC stuff lol

 

[cpubud]

Re: Trim Gauge - up is down....down is up

its suppose to appear backwards. think of it this way..the switchs are bow control, if you want the bow down push the switch up or forward and tabs go down and so does bow of boat.

 

[Shamfarlango]

Re: Trim Gauge - up is down....down is up

its suppose to appear backwards. think of it this way..the switchs are bow control, if you want the bow down push the switch up or forward and tabs go down and so does bow of boat.

That works perfect for my trim tabs...just not the selectrim