1975 Merc Tilt/Trim problem

[Rip n Lips]

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I have a older boat with a 115 merc. The Wiring harness for my tilt/trim came unplugged. After a struggle I finally got the rubber boot at the end with the 3 male adapters plugged in and the tilt down now works. Unfortunatley there is 2 wires that branch out before that plug that go to my tilt/trim up switch. They have female adapter ends on them and I don't know where they go to. I was told that they go to the Trim Limit Switch but looking around I can't find where that is? I have limited visibility to my tilt/trim motor buy was hoping someone could explain to me where that limit switch is or possibly has a wiring diagram I can look at? Thank You.

 

[Laddies]

Re: 1975 Merc Tilt/Trim problem

The trim limit switch was on the port tilt cyl. and most died within a year and the 2 wires on the boat harness just connected to gether so the engine would tilt and the wire pulled from the switch.

 

[Rip n Lips]

Re: 1975 Merc Tilt/Trim problem

The trim limit switch was on the port tilt cyl. and most died within a year and the 2 wires on the boat harness just connected to gether so the engine would tilt and the wire pulled from the switch.

The two wires both have female adapters, how can they plug into each other?

 

[Laddies]

Re: 1975 Merc Tilt/Trim problem

Make a adapter or clip them and use a solderless connector here's a wiring diagram.

 

[Rip n Lips]

Re: 1975 Merc Tilt/Trim problem

Thank you for the diagram, but i'm pretty sure I only have 1 solenoid which is connected to my trim pump?

 

[Laddies]

Re: 1975 Merc Tilt/Trim problem

It's the same thing except the single solenoid can't be used with a handle trim setup.

 

[Rip n Lips]

Re: 1975 Merc Tilt/Trim problem

I stopped at Valley Marine here in Yakima and talked to a couple guys that work there. They told me to check the relay on my engine. When I got home I pulled my cowling off and took a look. There was what appeared to be 1 wire that was corroded and broke. There was 5 or 6 wires all electrical taped together and that 1 wire appeared to be the only bad one. After I cut all the electrical tape off this is what I found...All of the wires need to be replaced. What is my best bet? Take it to an electrical shop or take it to a marine shop? How much do you think I am going to end up spending?

Thanks for all your help and input on my situation...

 

[Moody Blue]

Re: 1975 Merc Tilt/Trim problem

Maybe I missed something. Your motor does not (correct me if I'm wrong) have any relay on/in the motor relating to the tilt trim system. All tilt/trim functions are remote and separate from the motor. Not sure what those guys at the marina were telling you.

As far as the wire condition goes, that is typical of those vintage motors. You can buy new harnesses and just replace the whole thing yourself. Make notes regarding wire colors and where they connect AND how they are routed. Take photos to help jog your memory.

 

[Rip n Lips]

Re: 1975 Merc Tilt/Trim problem

Maybe I missed something. Your motor does not (correct me if I'm wrong) have any relay on/in the motor relating to the tilt trim system. All tilt/trim functions are remote and separate from the motor. Not sure what those guys at the marina were telling you.

As far as the wire condition goes, that is typical of those vintage motors. You can buy new harnesses and just replace the whole thing yourself. Make notes regarding wire colors and where they connect AND how they are routed. Take photos to help jog your memory.

Yea I don't know what the guys at the marina were talking about either. I finally got my Internal wiring harness all connected and now realize that the harness has absolutley NOTHING to do with why the tilt trim...I got the test light out and tried to do a little trouble shooting and took a quick pic. This is what I came up with. With the test light grounded on the negative terminal of the solenoid (black arrow) I touched the positive terminal on the solenoid (blue arrow) and got nothing. When I touched under the little rubber boot (red arrow) I have power...The blue wire should be a constant source of power correct? If I have no power to the positive terminal of the solenoid it has to be in the wiring right? I'm kind of lost on where to start here guys. If anyone can point me in the right direction before I have to take it in to a shop (especially one that already gave me faulty info.) it would be greatly appreciated. Thank you.

 

[justfish675]

Re: 1975 Merc Tilt/Trim problem

RIp n lips LOL I have heard that name before. You don't lurk around on walleyes first do you? Just the your name makes me miss jigging those eyes up on the fox river.LOL Any way go back thru the diagram and follow the wires. Make sure they are all connected correctly. I have a 78 1150 and after looking at the diagrams tracing out the problem was fairly easy. What color are the wires that go to no where. when I took mine apart I had two purple wires that were just laying in the bilge area. These went to the trim limit switch. Are you sure that your trim motor only has one slenoid? he is a link to a wiring book, it is a preview but the info shouold be there.
http://books.google.com/books?id=tA...oYjkCQ&sa=X&oi=book_result&resnum=1&ct=result

 

[justfish675]

Re: 1975 Merc Tilt/Trim problem

if you do have only one selinoid this maybe your set up don't know if the link will take you to right page but check page 315.
http://books.google.com/books?id=qyH2vqfQCZIC&pg=PA39&dq=wiring+harness+1975+merc#PPA315,M1

 

[Moody Blue]

Re: 1975 Merc Tilt/Trim problem

Working strictly from memory here. I have the same single solenoid trim unit as you.

The Red wire with rubber boot is HOT at all times. This red wire will be heavy gauge and should run from the battery directly to the large terminal on the solenoid. The blue wire is the UP signal wire from the trim control panel (as is the green wire). It is only HOT when you press the UP button on the control panel. The blue and green wires will be lighter gauge. The blue wire should connect to a small screw terminal on the solenoid. The green wire (DOWN from control panel) will run directly to the trim motor.

Hope this helps.

I have a wiring diagram for the single solenoid type somewhere. Will try to scan it and post it here tomorrow for you if I can.

 

[Rip n Lips]

Re: 1975 Merc Tilt/Trim problem

AHA! Thank you for the diagram. I was able to locate the 2 wires that come from the trim limit switch and get them plugged into the 2 strays. It still doesn't work but atleast it made me feel like I made progress . I brought back out the test light and I do have power to the blue wire to the solenoid. This leads me to think that the solenoid is bad? Is there anything else that I could check before I buy a new one to make sure that is infact the problem? Also if that is the case can I buy just a solenoid or do I have to replace the whole unit???

 

[justfish675]

Re: 1975 Merc Tilt/Trim problem

You can just buy a solenoid. They are like 20 bucks.

 

[Moody Blue]

Re: 1975 Merc Tilt/Trim problem

You can do this to check if the solenoid is bad or not.

Using a heavy jumper wire, say 10ga, jumper from the red wire on the solenoid to the blue wire that connects from the solenoid to the motor (not the blue wire from the control panel). This effectively bypasses the solenoid completely. There will be a spark when you make contact so be aware of it.

If the motor operates, the solenoid is bad. If the motor does not operate, then something else is wrong. Maybe bad ground connection or bad motor.

 

[Laddies]

Re: 1975 Merc Tilt/Trim problem

Yes

 

[Rip n Lips]

Re: 1975 Merc Tilt/Trim problem

You can do this to check if the solenoid is bad or not.

Using a heavy jumper wire, say 10ga, jumper from the red wire on the solenoid to the blue wire that connects from the solenoid to the motor (not the blue wire from the control panel). This effectively bypasses the solenoid completely. There will be a spark when you make contact so be aware of it.

If the motor operates, the solenoid is bad. If the motor does not operate, then something else is wrong. Maybe bad ground connection or bad motor.

Moody,
I used your advice to check the solenoid. At first the motor was a little hesitant to do anything, but after a couple small taps with a crescent wrench it had no problems making noise like it was working. The problem is that the engine still didn't raise but a few inches very slowly...I can't get the little screw out to see if there is any hydraulic fluid (oil) or add any more, someone put it in TIGHT, or it hasn't been checked since 1975...The guy at the electrical shop told me that there is brushes and armeture in the motor that could possibly be rebuilt? Is there a possibilty that the shaft that runs through the motor could be stripped or something? Obviously i'm going to start with the fluid but am also trying to weigh the advantages/disadvantages of buying a whole new unit rather than having the old one rebuilt if even possible?

 

[Chris1956]

Re: 1975 Merc Tilt/Trim problem

Fill screw is the stainless, slotted screw on the far right of the resvoir. I would hope it is not tight, since it desn't need to be. Use a hand impact driver to loosen it if necessary. Fill with 5W-30 motor oil, unless current fluid is red ATF, then use Dextron III ATF.

 

[Rip n Lips]

Re: 1975 Merc Tilt/Trim problem

The tilt/trim motor was full of water and the brushes are worn. New unit should be here tomorrow at noon. The url that JustFish posted no longer works. Can anyone get it to work or find the same diagram? Any help would be...helpfull... Thank you.

 

[Rip n Lips]

Re: 1975 Merc Tilt/Trim problem

http://books.google.com/books?id=qyH...merc#PPA315,M1

Anyone?