Oh, with the third wire I meant the regulator housing terminal to ground.....
Thanks for all your help and time.
I take the generator apart on the weekend and do the tests from the manual.
I bought it years ago as a backup....some remanufacturing job.
For my current 261 rebuilt for the coupe, I am thinking of going with an alternator, as I have heard they are required for a possible air-conditioning unit in the future.
Is that good thinking - and are there other benefits...?