3 wire trim&tilt to adapt to 2 wire system

[rejcruzn]

I have a 1990 Yamaha 150 HP outboard that is a 2 wire trim & tily system, green and blue wires. I replaced the complete assembly becasue the motor was bad and had lecks. After replacing the complete unit ( which was NOT easy ), going to attach the new units wires, pulling back the large rubber casing, it turns out the new unit's motor is 3 wires , green, blue and black. Can the 3 wired trim & tilt work with the 2 wire system. HELP..it was extremely NOT easy to replace the assembly.

 

[99yam40]

Re: 3 wire trim&tilt to adapt to 2 wire system

what was the unit you picked up from?
Apparently it was not for you motor, and I do not think it will work.
Black is a ground normally, but the 2 wire does not use a ground as it just reverses the polarity on the two wires to reverse the direction the motor turns

 

[Don S]

Re: 3 wire trim&tilt to adapt to 2 wire system

With the two wire system, your relays are reversing both power and ground through the motor.

With a 3 wire system, you have an up relay and a down relay that only puts power to the motor in the direction you want it to go.

Blue/sky/up
Green/grass/down

The ground does not change in the 3 wire system, only the power.

 

[glenn property of pam]

Re: 3 wire trim&tilt to adapt to 2 wire system

its not plug and play but it can be made to work. If you can supply more details on the new motor so we can confirm how the motor works then we can show you how to rewire the relay box on the outboard.
3 wire sounds like a older version of the hydraulic pump where green/black is up and blue/black is down (black is always ground). If this is how your 3 wire motor works then rewiring the relay box is easy.
Depending on where you bought the motor etc it might be better to exchange it and stay with a 2 wire but if it has been installed and scatched then it might not be returnable.
more details and pic will help us help you


edit: green/black down and blue/black up

 

[Capt Ken]

Re: 3 wire trim&tilt to adapt to 2 wire system

Actually it will work just fine. Your current solenoids are grounding the wires when not activated. When you apply power to one, it switches to applying power to that wire. So if you ground the black wire then install the blue and green wire to the proper solenoid, it will apply power to the correct wire. The wire not being activated will be grounded but that will not matter.

 

[RRitt]

Re: 3 wire trim&tilt to adapt to 2 wire system

that's not right cap ken. you can not ground green or blue at any time on a 3w motor. 3w motors use electro-magnets instead of permanent magnets. if you ground the green wire while activating the blue then you are energizing both the forward and reverse electromagnets. The motor usually just sits there and makes smoke.

the solution is to remove the switched ground from relays. If you are lucky, then you do not have proprietary relays. Bosch relays are $3 each and just replace existing 5pin N.C, relays with 4pin N.O. versions of same. But ... yamaha doesn't strike me as a company that would use the $4 universal part and miss out on the opportunity to sell you an $80 yamaha part to do the same thing. you'll probably have to identify the NC contact and manually cut the switched ground wire.

 

[Don S]

Re: 3 wire trim&tilt to adapt to 2 wire system

I agree with RRitt that you can't uses the 2 wire motor setup on a 3 wire motor as it is wired.
You can use the Yamaha relays and sockets, but you will have to completely rewire the sockets for your new setup. You will only be using 4 of the 5 terminals.

A few pictures of your present trim relay sockets and relays may help us figure out what wire needs to go where.

 

[Capt Ken]

Re: 3 wire trim&tilt to adapt to 2 wire system

When activating the blue wire, the circuit is between the ground and blue. The green should be neutral being it goes to a separate set of brushes than the one the blue wire uses. So it should not matter if it's grounded. The Sterndrive uses the same wiring and the trim motor is used on both types of solenoids.

 

[glenn property of pam]

Re: 3 wire trim&tilt to adapt to 2 wire system

When activating the blue wire, the circuit is between the ground and blue. The green should be neutral being it goes to a separate set of brushes than the one the blue wire uses. So it should not matter if it's grounded. The Sterndrive uses the same wiring and the trim motor is used on both types of solenoids.

intresting arguement. I was wondering is the unused brushes would act as a dyno which is why i would remove the grounds from the relay contacts.

 

[RRitt]

Re: 3 wire trim&tilt to adapt to 2 wire system

one of the brushes is typically connected to a common junction between forward and reverse field windings and the opposite brush to ground. During normal operation you get 6v across the armature and 6v across the field winding. by grounding the green wire you are energizing the reverse winding via the armature voltage. the typical result is smoke. maybe even fire if you wait long enough.