wire melts!!

[manggler]

1993 merc 40 classsic serial # 0D220441, bought a 3 wire trim motor that cam out off a merc serial #0G273296 (1996 -90HP 3 Cylinder outboard), then bought wire harness with relay from ebay(Mercury Outboard Trim Harness 819514A4 Relays 882751A1).

Now here is my delema, used the Merc Repair book for wire setup, everything works, the trim goes up and down ,but i can only go up and then I have to stop for a while before attempting to bring it down and the reason is the green and blue wire heats up so much that it melts if I do a full up and down cycle.

Any help out there would be much appreciated.

 

[matt9923]

Re: wire melts!!

I dont know to much about tilt/trim but maybe you need larger gauge wire. Im assuming the solenoid is next to the motor on the trim. The wire form the motor to the battery should be large gauge and smaller wires just for the solenoid switch. Look around for a trim/tilth electrical diagram.
Matt

 

[manggler]

Re: wire melts!!

Matt, first thanks for your response, but I do not think it would be possible to increase the wire size , the wires that really heats up is just the green and blue wire the comes out of the relay/solenoid.

I did try your setup and it still heated up, and then I tried the Merc manual book where it instructed me to hook up through the started solenoid and it still heated up the same.

 

[matt9923]

Re: wire melts!!

So the wires form the switch on the control box to the solenoid heat up when you do this? They even start melting? Those are just low volt switch wires maybe you have a bad solenoid and its shooting electricity up them an cooking them. I have seen this in my old ford 150. Fried my wires right to behind the dash. Try testing the solenoid,
Matt

OK take the solenoid off if you can IDK what it looks like exactly. Hook up a battery 2 the big terminals with jumper cables then get 2 smaller wire like the ones the size of you switch ones and attach them to the little terminals hit them together and see if the solenoid clicks. It will because you said it moves the trim. Hold those together for a little bit and see if they start to burn up if they do you need bigger wire or a new solenoid.

 

[Peter Eikenberry]

Re: wire melts!!

matt is right. Wire size is the issue. You are getting more amps through the wire than it can carry without overheating. This is due to the resistance of the wire. The larger the wire the less the resistance. I suggest you move two sizes larger.

 

[manggler]

Re: wire melts!!

Matt/Peter, I am leaning more to a new solenoid will do your test tommorow with a new solenoid and get back with , hopefully with some positive news.

great site, thanks again for all the help!

 

[manggler]

Re: wire melts!!

Matt, can you just clarify something for me, based on the Merc Manual the green and blue wire from trim motor connects to the green and blue trim relays and the black and red from the trim relay goes to the solenoid,if I was to setup like yours. where does the trim relay connects to or will I no longer need it?

 

[matt9923]

Re: wire melts!!

I don't have a motor with trim (im getting one) so i don't know the exact setup.
Could you take a picture of the trim unit and the wires?
You need the battery hook up and then the switch wires to the switch, i think you need the relay. Try to keep it how it is and see if the solenoid fixes it.
( the relay is for the 3 way type switch i think so you do need it )
Matt

 

[Chris1956]

Re: wire melts!!

Power trim motors are either 2 wire or three wire. If they are two wire, relays are used to change the polarity of the power. For example, if you want to trim up, +12V is sent to the blue wire and the green wire is grounded. If you want to trim down, +12V is sent to the green wire and the blue is grounded.

on a three wire trim motor, two solenoids are used instead of relays. One of these close and send +12V to either the green wire Trim down) or the blue wire(trim up). The third wire is always black and grounded. In the 93-96 time frame Merc went to 2 wire motors and relays. When you buy replacement trim motors for a 3 wire system, you sometimes get a 2 wire motor and two relays. The burden is on you to hook it up correctly, and you chuck the solenoids.

Do you think this could be your issue?

 

[manggler]

Re: wire melts!!

Talk about a wealth of knowledge one gets from this site!!, Chris, after talking to a mechanic ,he advised me the same as you have and confirmed Matts setup is accurate.

Great Site!!!! Thanks to all!!

 

[manggler]

Re: wire melts!!

Matt, from my high school days (way , way, back!!) ,in my auto class I remember that the wire used for bat to solenoid is 4gauge, in your setup what would you suggest wire size for all?

 

[matt9923]

Re: wire melts!!

The positive from battery to switch i would use 12-14 gauge.
Up and down i would use 12-14 gauge.
And for the battery to the solenoid/trim motor i would use 4 gauge. Maybe a little smaller....
See what you have now, the main electric lines have to do a lot of work so the need to be big. The switch wires don't need much. You can probably use what you have but you might need bigger and newer wire.

Advanced auto parts has a 100ft roll of 14 gauge wire for like $12.
Hope this helps
Matt

 

[manggler]

Re: wire melts!!

Matt, reference to your diagram , trim switch connects to "s" or "i" ( if i remember "s" is starter and "i" is ignition)is this correct?, if so then the small negative would go to"s" and the trim switch would go to "i" ? would appreciate your advise thx.

 

[matt9923]

Re: wire melts!!

I'm not sure what you are asking. Are you rewiring the whole thing or going threw your control box. If your going threw the control box I'm not relay sure i don't know which one you have. Maybe some pictures of what your doing and i can help you. what are you using the ignition for?
Matt

 

[matt9923]

Re: wire melts!!

 

[manggler]

Re: wire melts!!

pm you

 

[matt9923]

Re: wire melts!!

The big terminals are power. small ones are switch wires.
I'm tired ill help you tomorrow.
Matt

 

[manggler]

Re: wire melts!!

Matt, again you have been a great help, I tinkered with it and got it working thahks again.

ray

 

[matt9923]

Re: wire melts!!

Good I'm happy you got it going. Now you don't have to worry about the trim not working and will be able to trouble shoot it easier if anything happens again.
Matt