2 wire powertrim unit/3 wire powertrim unit interchangeable?

[dfrants]

i have a 1999 125hp Merc with a bad 2 wire power trim unit. this outboard has the 2 wire relay system. i have a 3 wire trim unit here and was wondering if it can be rigged to work with this system or do i have to switch all the electronics to the 3 wire solenoid system?

 

[achris]

Re: 2 wire powertrim unit/3 wire powertrim unit interchangeable?

The 2 wire unit works by switching the power direction between the wires. The 3 wire unit works by having the black wire grounded, then switching power to either the green (DOWN) or the blue (UP)... To change from 2 wire to 3 wire, you are going to need to change all the solenoid wiring too...

Chris...

 

[dfrants]

Re: 2 wire powertrim unit/3 wire powertrim unit interchangeable?

so does that mean on the 2 wire system the blue is the power and the green is the ground when the up button is pushed and vise-versa when the down is pushed?

 

[achris]

Re: 2 wire powertrim unit/3 wire powertrim unit interchangeable?

Please post the serial number of your engine....

If you have a blue wire and a green wire, then you may not have a 2 wire motor...

(2 wire motors have a blue and a black wire)...

 

[Chris1956]

Re: 2 wire powertrim unit/3 wire powertrim unit interchangeable?

3 wire PTT motors usually have a blue, green and a common black (ground) wire. 2 wire PTT motors usually have a blue and green wires. Putting +12VDC on blue wire and grounding the green wire (2 wire motor) spins the motor in the up direction. switching polarity spins the motor in the down direction.

On a three wire system, the black wire is always grounded. Putting +12VDC on blue (nothing on green) spins the PTT motor in the up direction. Putting +12VDC on the green wire spins the PTT motor in the down direction.