The way I understand your OMC wiring diagram is the orange wire coming up the harness to your ammeter also goes to the key switch to provide power for everything else via the purple wires. That feed can be substituted with the red battery wire that is going to the other side of the ammeter.
That would be cool if I eliminate the ammeter and just change the power source for the other gauges from orange to red. To add more confusion, under the dash there is another plug. I suppose the built the dash assembly and plugged it into a harness that runs back to the engine, but wouldn't you know it, some of the wire colors change again! I can see how power and ground is daisy chained under there so that shouldn't be too difficult.
If you had the normal alternator then yes, but your one-wire alternator doesn't require the exciter wire so you can leave it disconnected. Purple from your engine-end harness goes to one side of the ballast resistor, the purple/black wires coming off the other side of the ballast go to the ignition coil and starter solenoid.
The white wire going to the slave solenoid is your start trigger from the keyswitch which is equivalent to the newer yellow/red color code. The white/red wire going from the slave to the starter solenoid is what triggers your starter.
Good cuz thats about all I got left.
As for what to connect to the alternator it should be a large gauge red or orange wire from the output terminal to the main battery lug on the starter solenoid, probably one of the large red wires already there.
Unfortunately not. There is nothing from the starter to the alternator directly. I am guessing it is fed back from the ammeter? There are 3 wires on the main starter lug. The main from the battery, one to the slave solenoid and one that goes into the harness and up to the dash.
If I am following you, what you've are saying, it sounds like once I swap out the ammeter for a volt meter, I no longer need the heavy gauge wire under the dash. Remove that and substitute the power it was supplying using the large red, then add a 4th a heavy gauge red or orange to the starter main lug and run that directly to the alternator? Do I have that correct?
You can see the orange in the pic currently running directly from the plug to the alternator
[/quote]
Its sure going to be nice to be rid of this rotten stuff.