I've always found the easiest way to determine a spark/fuel issue is to remove the sparkplug, pour a few drops of good gas directly into the sparkplug hole (this can be a little difficult if the sparkplug is oriented horizontally - you can find a way, though), replace the sparkplug and try to start it. (Careful with the gasoline. I don't want to be responsible for you blowing yourself up!) If it fires and runs for a few seconds, you know you have spark and your issue is with fuel (or air). You said you have a new carb and fuel lines. There may be an air leak in the intake manifold; check all the screws/bolts to make sure they are tight. If they are loose, tighten them sequentially (even if there are only two) a little at a time. Don't overtighten them - you don't want to break one off!
If it won't fire over with fuel poured directly into the spark plug hole, then you may need a new magneto. They can fail suddenly. Pretty easy to find online, usually not too expensive, and a fairly easy install if you have basic tools (which sounds like you do). There's also a lot more detailed diagnostic info for deciding if it's the magneto online, too.
Personally, I would never use fuel containing ethanol in one of these engines. Luckily, I live in a State where uncontaminated gasoline is still available.