1978 85 hp Johnson Trim/Tilt Changing from 3 wire to 2 wire motor

[enduro155]

I am looking at changing my old 3 wire trim/tilt and replacing with a 2 wire unit.
What needs to be replaced, or can I simply tie into the old harness less the black ground?

Thanks,

 

[wmconway]

Re: 1978 85 hp Johnson Trim/Tilt Changing from 3 wire to 2 wire motor

You will need the relay box that came with the 2 wire system. The 2 wire system is reversed polarity. Ie positive on one wire and negative on the other will raise the motor, then switch the wires and the motor will lower. The relay box switches the polarity for you.

 

[emdsapmgr]

Re: 1978 85 hp Johnson Trim/Tilt Changing from 3 wire to 2 wire motor

You may have some issues to deal with. It depends on what year 2 wire system you will be using. The 1984 and later 2 wire power trim control boxes get their power from the main engine wiring harness under the cowling. Those 84 and later boxes mount under the cowling and your engine does not have any mounting holes for the box-usually screwed into the outer exhaust cover. The early 2 wire system (1983 and earlier used control boxes that were very similar to your original 3 wire box. They were remote mounted and had their own power wires that went direct to the battery, like the engine does.

 

[enduro155]

Re: 1978 85 hp Johnson Trim/Tilt Changing from 3 wire to 2 wire motor

It appears to be an older unit. But how can I establish that.
In addition, there was no relay so I would have to pick one up.

 

[enduro155]

Re: 1978 85 hp Johnson Trim/Tilt Changing from 3 wire to 2 wire motor

Could I not buy a dpdt relay, wire it in and hook directly to the battery?
then hook up the wiring for the control from my existing wiring?

 

[emdsapmgr]

Re: 1978 85 hp Johnson Trim/Tilt Changing from 3 wire to 2 wire motor

The control boxes with the 3 wire system used a solenoid for the up movement only. When they went to the 2 wire system in mid 1981, they they replaced that single solenoid with two interchangeable relays. One for the up movement, one for the down movement.

 

[enduro155]

Re: 1978 85 hp Johnson Trim/Tilt Changing from 3 wire to 2 wire motor

How would a schematic look for this set up?

Thanks,