OK, I got it running just fine today, but don't ask me exactly what is wrong with it, I'm just relieved it is finally running right.
The first problem I fixed was a spun flywheel, but that did not fix it.
Here is what was not wrong: I installed a total of 5 different carbs, and 2 different coils, and 2 different plugs. Also checked to ensure both the impulse line and fuel line were clear. And it still would not run!
What I did today: Installed another fuel tank (includes new fuel line and filter, and new tank vent), replaced the impulse line (just in case) and added another washer spacer to the impulse line nipple.
Not sure exactly what it was, just relieved that I fixed it! Was driving me crazy! My best guess would be the fuel line and filter, even though I could blow through them, perhaps it was collapsing.
I'm glad the problem WAS NOT the D Dave carb, which is what is on it now. I'm now 3 for 3 with those carbs, a significant improvement!