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tilt and trim question 1985 140

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draven620

Regular Contributor
I just have a quick question i have a 1985 140hp mercruiser and my question is this.When i was cleaning the boat up for the water in a couple of weeks i noticed that there are a couple of wires that look like the plug of a lamp they run from a connector attached to a plate that is right below the 50 amp breaker.It runs down towards the lower unit but i do not know if it is the trim limit switch wires or the trim sender wires.The main reason i am asking is because the wires look like they have ate them self away and the coating falls apart when it is touched.And my trim limit funtion is not working but i just want to make sure these are the problem or not so i need to know if they are limit switch or sender wires so i know if i need to look somewhere else.
 
Re: tilt and trim question

So your saying it is the actual trim wires not the trim limit or trim sender wires so can I remove the wires and install new ones in it there place.
 
Re: tilt and trim question

sure you can replace them, but first make sure you have the name of a good shrink.

And make sure you have maybe 2 days of free time.
 
Re: tilt and trim question

what do you think should i take it in and get it replaced or is repairing the wires a feasable option you guyes are the professionals.
 
Re: tilt and trim question

IMAG0161.jpg

IMAG0160.jpg

IMAG0159.jpg
These are the pictures I have been doing some research and i think they are the trim sender wires and i do not have a trim sender gauge so they shouldnt really matter if they are the trim sending unit wires. The other set of wires that are coming out of the lower unit are attached over by the tilt and trim pump, And they look to be in good shape.So am i correct are they the sending unit wires they install by the 50 amp reset switch on a bracket.
 
Re: tilt and trim question

OK, not stealing your thread, but, I too am wondering where those wires go on my boat. On my boat, mercruiser OD, they connect to a terminal mounted on the transom wall. Two wires go through the transom to the outdrive switch and this "double wire" goes somewhere. Mine has two ends which go over a small post of some kind. Could it be the 50 amp breaker? Thank you, Bob
 
Re: tilt and trim question

I have an 85 twin and it would appear that they are the "lamp shade" wires that run to your drive and then to the trim limit switch and trim indication switch. If you look at your drive on both sides you should see a round flat cover about the size of a silver dollar which are the switches. Yes you can try and splice in some proper wire inside the hull but it is likley to be so corroded as to be un-repairable. (I tried it.)
You cannot buy the wires as a seperate part number from Merc any more because of this issue. You have to replace the switch (and some one correct me if I am wrong) but you have to also remove a bellows to route the wire properly. If you don't have a trim guage then you probably only have to replace one switch. That choice of wire type in this application was....questionable.

Look at replacement when you service your drive again and the boat is out of the water. The trim limit function is important for safety and not over reving the motor if you over trim underway.
 
Re: tilt and trim question

On almost all current outdrives there are two round plastic adjustable "caps" on the left and right sides of the gimbal ring.

the one on the left (looking at the outdrive from the back of the boat) is the TRIM LIMIT SWITCH. The one on the right is the trim level sending unit (varialble resistor like in your home for adjustable light dimmer)

The trim switch sets the usable trim out hieght before or at cavitation.

The trim sender setd the trim guage to outdrive position.

Each has two wires that look like a house hold extension cord.

The trim switch interacts with the trim switch wiring from the controll handle.

The trim sender connects to a junction block or bullet connectors that feeds the guage on the dash. The Senders black wire goes to the brown or brown with a white stripe, The other wire goes to a good ground.

The trim switch connects to two blue wires somewhere near the trim pump normally.

The trim up button gets power and then it travels thru the trim switch and when the trim hieght is reached (that you adjust by turning the switch rotationally) it shuts the 12 volts off going to the trim up solenoid. When you push the TRAILER button it bypasses the trim limit switch and activates the up trim solenoid.

Hope that makes sense.

If you do not fully understand then you need a schematic to see how the wiring is done.
 
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