Well I wrote too fast. The started and ran for a day. None of the long crank time, and initial stumbling before smoothing out to run normally. Then the problem came right back. the idle isn't really all that smooth but the stumbling stops after feathering the throttle to help it catch, start and run. After it warms up it is smooth as it was out of the factory decades ago.

Thanks, guys for your posts. While it's not fixed yet this gives me good direction to figure it out. This isn't the first time in my life where I've run into an intractable technical or mechanical problem that makes no sense and I presume it won't be the last. Keep 'em rolling!