G scale motor +/- ?

[bulber dude]

Trying to install a decoder on a clementine engine and can't figure out which connection is + and which is - on the motor. Is the black wire + and the red wire - or

[snowshoe]

Im not an expert but I would say red  is + Black is -   It should all be universal when it comes to wiring

[bobgrosh]

the plus side of the decoder output should be labeled "+" or it should be an orange wire.

Prior to installing the decoder, the motor should have been wired with the plus side of the motor to the right (engineers side) of the loco's track pickups.

Normally this wire would be red!

Got that! red, right "+".
The motor is not marked with a "+" on either connector, the "+" lead is simply the one that makes the loco go FORWARD when a positive voltage is applied to the. It is possible that a motor, with a red wire soldered to one lead would make one loco go forward, but if moved to another loco would make that second loco go backward, It all depends on the orientation and gearing of the loco.

Check the loco first on a DC supply, Set the direction switch so the loco goes forward.

Install the track pickup wires to the decoder, (red to right rail, black to left rail.

Temporarily attach the orange and gray wires to the motor.
Now put the loco back on the track FACING THE SAME DIRECTION, DO NOT CHANGE THE DIRECTION SWITCH on the power pack.
Give the loco a little throttle and it should move FORWARD, if not reverse the orange and gray wires at the motor. Now you can connect up the rest of the wires.

[bulber dude]

Thanks for the information. I appreciate the help.

[rperego]

I just put an NCE decoder in a Clementine and as with all other Bachmann's I've converted I had to hook the orange decoder wire to the black wire on the motor - in other words in reverse of what one would think.