Mercury 1986 inline 6 90hp trim relay problem

[endurance]

Hi Guys,
Picked up a merc 90 hp inline 6 with out power trim.
Just got. A 3 wire power trim this motor normally has
2 solenoids one for up the other for down. I picked up a. Johnny control box
With 2 relays inside. Hook up the first relay worked fine up using the blue wire
Then switched to green wire to check trim motor to see it go down it did worked fine
So I. Hooked up the other relay and the problem occurred. Motor going down was slow its like
By hooking up the other relay it actually cut the power. Any of you Guys have the answer it would
Greatly be apppreciated.

 

[fishfeatures]

Re: Mercury 1986 inline 6 90hp trim relay problem

have you wired the motor and switch to the relays like so ?

 

[Faztbullet]

Re: Mercury 1986 inline 6 90hp trim relay problem

You cannot use the relay system on a 3 wire motor as the blue/green are actually a field in motor. The relay set-up flip/flops the ground on the 2 wire system ,in other words green becomes ground and blue is supplied positive to make it turn in up direction. A 3 wire motor black is ground and either the blue or green is energized to determine if you want up or down that the reason for solenoids.

 

[RRitt]

Re: Mercury 1986 inline 6 90hp trim relay problem

in order to use a 2w relay system with a 3w motor ... you have to pull the ground wire off post 87A.

generally speaking, the fat black wire goes to post 87a (contactor) and a small jumper wire goes to post 85 (control). In this case you use a jewelers screwdriver to remove both wires and then stick the fat wire back into post 85. Tape, sleeve, or heatshrink the small jumper in case you ever convert back to 2w. Doing this makes the relays behave as solenoids. If your boat had existing solenoids then you no longer need them. They should be removed. They probably are not worth keeping since relays tend to be a more easily serviced technology. As regards your switch - post # 86 should directly wire to your switch. If the motor operates in reverse then flip post #86 from one relay to the other. you may have multiple switches wired in parallel - for example one at captains chair and one at transom.

 

[Faztbullet]

Re: Mercury 1986 inline 6 90hp trim relay problem

The above post will work but take the black wire from trim motor to engine ground, not relay. The relays may last a while as they are rated about 30amps asthe old style trim motors have a large surge when operative verses a magnet motor (2 wire)..

 

[endurance]

Re: Mercury 1986 inline 6 90hp trim relay problem

First. Thank you to all. RRitt removed wire 87a. .
the end of wire 87a is. Connected to 85 which is the ground.
I am unclear on 85 &87a
Do I remove ground wire from 85 and stick it in 87a and attach it to engine ground?
Regarding 87a jump it where,cause its end is in 85 thanks for helpng clear this up

 

[RRitt]

Re: Mercury 1986 inline 6 90hp trim relay problem

2w motors do not have a common ground. you just flip polarity and they spin the other way.

3w motors DO have a common ground (black wire and/or motor frame). The blue wire is up and the green wire is down. If you accidentally connect ground to either the blue or green wire then your motor will eventually burst into flames.

relays are little electro-magnets that pull a switch. The relay will noit work if the electro-magnet does not have a ground. post 85 is the ground wire for relay control.

87a goes through the switch and is connected to the motor depending upon switch up/down operation. When the blue wire is recieving 12V the relay will automatically connect 87a to the green wire. Ground MUST be disconnected from post # 87a on both relays or you will burn something out.
85 is control and must remain connected. If 85 is not connected then the relay won't operate.

 

[endurance]

Re: Mercury 1986 inline 6 90hp trim relay problem

RRitt almost there here is where I'm at 85@ ground
87@battery (hot)) 86@trim up switch 30@trim motor
Blue wire up (blue sky up green water down) only terminal left 87a,
Where exactly does it go RRhitt you ruled out 85@ground
So its either 86@trim switch blue or green wire Or @30 trim motor directional wire blue or green or
87@battery thanks in advance for making it Crystal clear.

 

[smokeonthewater]

Re: Mercury 1986 inline 6 90hp trim relay problem

It might help if you understand the relay... there are two terminals (85, 86) that when energized with positive and negative throw a switch and three terminals that one (30) is common and the other two (87, 87a) are switched between by the first two being energized


So for this project you need two relays.... both are wired the same except one is for up and the other is for down....
wire 12v positive (12 AWG) to 30, the green on one relay and blue on the other blue to 87, ground and positive (one must be switched with your trim switch) to 85(+) and 86(-), the black on your motor should be connected to the battery negative. the wiring to 85 and 86 can be small gauge like 18 AWG as it carries very little current

 

[RRitt]

Re: Mercury 1986 inline 6 90hp trim relay problem

RRitt almost there here is where I'm at 85@ ground
87@battery (hot)) 86@trim up switch 30@trim motor
Blue wire up (blue sky up green water down) only terminal left 87a,
Where exactly does it go RRhitt you ruled out 85@ground
So its either 86@trim switch blue or green wire Or @30 trim motor directional wire blue or green or
87@battery thanks in advance for making it Crystal clear.

post 87a is just open. no wires connected.

 

[endurance]

Re: Mercury 1986 inline 6 90hp trim relay problem

Great RRhitt,

Thanks
Everyone who contributed to this post thanks I apppreciate it
Keep sharing...
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