Which of these wires engages starter. I believe it is the black and white thick one but want to be sure and I need to know which of these would be a good keyed power source for my ignition box.

 

If you look at the wires from the front harness which connect to the wires in the pigtail, the B/W wire found in the plug w/the Black wire has power w/key to on and start. The Black/Red wire in the plug w/the Blue wire (again, front harness side) receives power w/key to on but not start. B/R wire in its own plug receives power w/just key to start.

 

So yes on the b/w wire for the starter and b/r for keyed power? Im actually doing a new wiring just ran into this as a snag, but no engine harness to lead back from.

 

Reposting the pictures not sure what happened.

 

The W/R wire and B/Y wire should be together in one plug which has both of these wires. W/R receives constant voltage from the main fuse. The B/Y wire would connect to the B/W wire of the front harness and this is the wire which has voltage w/key to start and key to on. This means the voltage does not cut out on this wire w/key to start and then resumes when the key reverts to the on position.

The thick B/R wire in the pigtail is for the starter. The B/W pigtail wire has voltage w/key to on but not key to start. Thus if you have an item, for example, and you want it powered w/key to on you have two choices. If you want it powered w/just key to on and not while starting then you want to use the B/W wire. On the other hand, if you want to power an item while starting and with w/key to on then you would select the B/Y wire.