Ok The weather and my time to work on it lately have not been in sync.
 
I do have a new spark plug, I changed it out several times during this just to rule it out.
 
I have a picture of the throttle set up, sort of, it is buried and hard to photograph but I will try to upload that later tonight possibly. It's a typical 1973 Horizontal shaft motor with an updraft carburetor throttle connection is mid linkage of governor rod, and a separate manual choke  
 
I have tried to run it without the kill switch wire on there, (especially when I initially look for spark during coil replacement) I have rung out all the wires and the switch, if those are malfunctioning then I would not expect any spark, yet I am getting backfiring through the muffler and carb like the timing is way off again.
 
I appreciate all the help and attention here, I sure need it, and will update everyone as soon as I can get back to it.

Is it like this?

Yes exactly the one
Not sure how upload the pic but here's a try

Do you see spark at the spark plug, when attached to the coil, grounded to the head?
 
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Scott ;
I haven't had a chance to really work on it this weekend, or lately, I hope to get back to it tomorrow or Tuesday 
But if I were to guess "Yes" it gets spark. because it got spark when I installed and tested it before final assembly and then it ran for those 20 minutes or so, and then it must be sparking to cause the loud backfires in the muffler and the carb, but I will be checking for that as soon as I can put it back together, the flywheel nut is off from checking the keyway, which is still good, but had in the past operational running, sheared off, I am reluctant to assemble it back together at this point because I have done this 1000 times with limited sucsessful results, I was really hoping someone would see the errors of my ways and point out perhaps a good quality part that would instantly solve all my problems, yeah right huh? LOL But gauging by the line of questioning I will be re-assembling it all and running these tests. The upside is I am so good at teardown and reassembly now I could probably do it in my sleep in 2 seconds flat like a nascar pit crew with my eyes closed.Thanks again I will keep everyone posted. 

So do you currently have points and a condenser?
 
If so, how do the actual contacts on the points look?
They can be cleaned up with some fairly fine sand paper if need be.
 
Are they opening and closing with the correct gap?
 
If the head is still off, try spinning(with your thumb) the top of the valves 
when their closed.  They should not spin when seated.
 
What's the current compression once assembled?
 
And definitly, check for spark again-after re-assembled.