Trim Guage Inaccurate

Proselect

Petty Officer 1st Class
Joined
Aug 17, 2009
Messages
237
I just bought a used boat a few weeks back and the trim guage didn't work. The guy told me it had to be calibrated, but after some digging I found he must have been full of crap. I did some testing and found that the sending unit was bad. I ordered a new one which wasn't cheap for a unit that just tells you where your trim is at. The guy before me replaced all the gauges on the dash with white ones except for the tirm guage, which was black. Me being particualar about things ordered a new teleflex guage to match the others right away as long as I was replacing the sending unit. I have it all hooked up, but when the trim is all the way down the guage reads below the down mark. When trimming up it doesn't move at first and then all of a sudden jumps near the top of the trim. Then the guage reads about 3/4 (or a little higher) trimmed up. Anybody else have this problem or have a remedy to get this thing to read right on? The sending unit I put in is a factory replacement right from evinrude and the resistances read right on. The guage is an aftermarket teleflex. Any tricks or help would be appreciated. Thanks in advance guys. By the way, this is on a 1994 Evinrude 112spl motor.
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: Trim Guage Inaccurate

If you can see the motor from the helm, probably not worth messing with. I have none on my boat with 175HP twins, and do fine w/o any.
 

SparkieBoat

Captain
Joined
Aug 17, 2009
Messages
3,643
Re: Trim Guage Inaccurate

sounds like the sending unit or the gauge is bad..as long as you have all the wires properly connected..and it was properly installed..which I will just assume you double checked that already. Maybe someone can give you the ohm test for the sending unit so you can test it...and maybe test the gauge on another unit that is known to work. My bet is a bad sending unit.
Sparkie
 

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
Re: Trim Guage Inaccurate

The factory sevice manual for my 1988 110hp Johnson has instructions for adjusting the sending unit.
wilde1j is right, the trim guage is not necessary as trimming the motor properly differs greatly depending on current conditions such as but not limited to total load in the boat, how the load is distributed, wind, waves etc.
The sweet spot one day can be quite a bit different the next day so where the needle on the guage points is kind of irrelevant, you do it by feel.
Sounds like you and I are alike however in that we need things to work properly and without compromise, so Im sure you will eventually resolve this issue.
If you dont have a factory manual you really should invest.
thats my 2 cents worth. Good luck.
 

Proselect

Petty Officer 1st Class
Joined
Aug 17, 2009
Messages
237
Re: Trim Guage Inaccurate

Thanks for the reply guys, I know what you mean by trimming it by feel and it not always being the same. Most the time going from fishing spot to fishing spot I really don't need to mess with it anyway.

Anyway, I went outside tonight to get to the bottom of this and it turns out the brand new sending unit it garbage. I have a sneaky feeling the dealer is going to fight me on this. I am going to call tomorrow and see if they will take it back and order me a new one. I can prove to them its junk by ohming it out, the thing goes bonkers at times, and at others works only on the up scale then drops sudenly to the down side. What a piece of crap!! I have the reciept, but I think I remember a sign in the shop saying all electrical parts sales are final with no retrurn, but I am going to fight this till the end tooth and nail if I have to. The damn thing cost me 83 bucks plus the gas to drive there and back to order, and there and back to pick it up. To top it off, it is a royal PITA to change when you have to snake all the wires through the trim harness. Wish me luck guys. I will update later with my results.
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: Trim Guage Inaccurate

Not telling you what to do, just what I did.

I threw it away, but the 2 wires for the trim unit are very usefull for hooking up a temperature guage/s.
One sensor in each bank and a switch to go between or get 2 guages.
 

SparkieBoat

Captain
Joined
Aug 17, 2009
Messages
3,643
Re: Trim Guage Inaccurate

yay I was right about the sending unit...I really do like the temperature gauge suggestion..I may actually do that myself.
Sparkie
 

Proselect

Petty Officer 1st Class
Joined
Aug 17, 2009
Messages
237
Re: Trim Guage Inaccurate

That is not a bad Idea about the temp guage. If I don't get my money back out of this sending unit I just bought then I will probably go that route. Good idea guys!
 

kencat

Seaman
Joined
Sep 11, 2008
Messages
51
Re: Trim Guage Inaccurate

Mine is acting the same way - 88 60hp.

I'm thinking it's a ground problem. Looking at the parts schematic, there are two terminal rings coming from the unit and wires, and another ground wire from the transom bracket near the sending unit to..... I'm not sure, the motor ?

Anyway, unless there is a proper test in the manual spelled out for these, ohming the two wires with out a proper ground could be misleading.

This is all just a gut feeling at this point, but the chance of getting a bad new unit is pretty low I would think.

Tear the old unit apart and see what makes these tick......and post some pics :D
 

tmfd

Petty Officer 2nd Class
Joined
Aug 14, 2009
Messages
132
Re: Trim Guage Inaccurate

The factory sevice manual for my 1988 110hp Johnson has instructions for adjusting the sending unit.
wilde1j is right, the trim guage is not necessary as trimming the motor properly differs greatly depending on current conditions such as but not limited to total load in the boat, how the load is distributed, wind, waves etc.
The sweet spot one day can be quite a bit different the next day so where the needle on the guage points is kind of irrelevant, you do it by feel.
Sounds like you and I are alike however in that we need things to work properly and without compromise, so Im sure you will eventually resolve this issue.
If you dont have a factory manual you really should invest.
thats my 2 cents worth. Good luck.

Where do you get a factory manual, I have Clymers and Seloc, checked both out from library. Is that what you are talking about or is there a source for original manuals? I have an '88 60hp Johnson.
 

kencat

Seaman
Joined
Sep 11, 2008
Messages
51
Re: Trim Guage Inaccurate

Where do you get a factory manual, I have Clymers and Seloc, checked both out from library. Is that what you are talking about or is there a source for original manuals? I have an '88 60hp Johnson.

Take a look at the bottom of Jonesg's post - links are there for factory service manuals.
 

tmfd

Petty Officer 2nd Class
Joined
Aug 14, 2009
Messages
132
Re: Trim Guage Inaccurate

Take a look at the bottom of Jonesg's post - links are there for factory service manuals.

Thank you, just to let you know Jonesg's, the bottom link is not quite working right.
 

Proselect

Petty Officer 1st Class
Joined
Aug 17, 2009
Messages
237
Re: Trim Guage Inaccurate

Well I called the dealer about the part and after some arguing it turns out there is nothing that can be done. I am stuck with an 80 dollar paper weight. They said there is no return on electrical parts unless they install them. I do see their point, there are a lot of yahoos who can fry electrical parts by not knowing what they are doing. In my case by testing this thing out it is faulty. By comparing it to the old one is seems if you put sideways pressure on the "knob" portion that turns it will read right sometimes. It just seems they used a cheap potentiometer in the things. I took apart the old one and dug out the potentiometer and I plan to run to radio shack and see if they can come up with something of the same thing. If that is the case I can fix it myself for about 5 bucks. If I have no luck then I am going to go with the temp guage suggestion, which is probably a smarter idea anyway. It seems more important to know you motor is staying cool rather than where your trim is. Afterall, I am not out on the lake for speed.
 

kencat

Seaman
Joined
Sep 11, 2008
Messages
51
Re: Trim Guage Inaccurate

jonesg, FYI

your link to marineengine.com doesn't work. You have an "s" on the end of marineengine that shouldn't be there.
 

Proselect

Petty Officer 1st Class
Joined
Aug 17, 2009
Messages
237
Re: Trim Guage Inaccurate

Well, I have it fixed. I took apart the original sending unit by digging out the epoxy filling on the back side and taking out the potentiometer. I then went to radio shack and matched up on the best I could. The smallest they had was a 250V .25a 5K ohm one. I said for 3 bucks I will try it. Turns out I was able to tune it in pretty good. I dug out enough of the epoxy to get the pot fitted in the unit perfectly. I then soldered on two wires to the right terminals and modified the hole in the arm to slide tightly onto the shaft. upon playing around with the settings it was looking good. I then packed a little piece of perfectly cut thin cardboard on top of the pot with two holes in one for each wire. I then filled it all in with 5 min epoxy. I put the lever and spring back on and wired it up and got it bolted to tune it. Once I had it tuned I put a dab of epoxy on the shaft and lever to keep it from moving. Now when I get to the very top of the trim the needle on the guage is right on the up mark. When it is all the way down, though, the needle is down below the down mark actually on the word down on the guage. I just put a little mark with a red paint pen to know where down is and all is good. It is amazing I wasted over 80 bucks on the correct OE part that was junk, for which they would take back(my loss taken in the rear), and I rebuilt the original for less than 5 dollars and about 3 hours time. If I ever had to do it again I think it would take less time. I wish I had pics of the whole process but I didn't take any. Thanks for the help guys, this ends my story.
 

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
Re: Trim Guage Inaccurate

Yeah a happy ending!!
Sounds like you are somewhat of an expert in electronics and very resourseful to boot.
congrats on a job well done.
 

Proselect

Petty Officer 1st Class
Joined
Aug 17, 2009
Messages
237
Re: Trim Guage Inaccurate

I am far from an expert on electronics, but I am a master auto tech as a career. Most of this boat stuff is cake compared to the complicated network of computers on cars these days, and I spend most my days diagnosing electrical and drivability problems. I was a proud and a little surprised of my self on how well it worked. We took the boat out last night and it is nice now to know when you are at the top of the trim just by a glance, even though it only needed trimmed about half way up for top speed. Hopefully the more i learn will result in me being able to help some of you guys some day. This is a great forum. Also the iboats store is nice too. I ordered a rectifier to replace my bad one and they had a very reasonable price and only two days to get here. Thats better than any dealer by me within 40 miles, and I don't have to drive then!
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: Trim Guage Inaccurate

iBoats is great for parts,
the only thing I bought from a dealer was tie wraps.
:D
 

mikesea

Lieutenant Commander
Joined
Oct 1, 2006
Messages
1,830
Re: Trim Guage Inaccurate

I must compliment you on your persistance.Most of us gave up on the trim indicators after it broke,which usually dont take long,if the mechanism spring dont break,a wire will burn,the unit itself goes bad as u found already.Hope all else goes well for you,seems like you can tackle anything thrown at ya.That is a MAJOR asset when it comes to marine.
 
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