i will definatly check out the start button. Im sure i seen a few posts on that somewhere here. I tried it again today. Fully charged the battery, cleand the plugs, and drained the carbs. Got some backfire again. Then after several tries she finaly fired up. However it would not fire with the choke on. I had to keep twisting the trottle to keep her alive. As soon as i stopped reving it cut out. I played around with the mixture screw which led to it firing in the first place then when i played with mixture screw again it would not fire. Im thinking now more on a fuel issue than mechanical. It started and thats a huge step in the right direction.Can't rule out the cdi yet. Not sure what tests there are for it, check the manual.
You have decent spark, but is it at the correct time.
Something about the start button, it means something, but on this system I'm not sure what. That symptom has been mentioned here before, but I'm not sure if anyone ever posted their fix. Never hurts to try the forum search.
Sometimes on old points ign systems, running only in the start position, meant a defective ballast resistor. But the ballast resistor on those old systems was there to keep the points from getting more than 9v, to reduce burning of the contacts. Could be something similar happening in the CDI, because there is that white/red wire between the start button and the CDI. The ignition timing could be going numb when you release the start button.