You didn’t say how long the engine runs when it starts. Does it die right away, does it run for 2 seconds? 5 seconds? If it starts, I suspect everything is OK as far as spark and carb adjustments. So don’t go messing with the mixture screws until you get it to run.
I’m pretty sure you’re not getting enough gas to the float bowl and it might be full of crap along with your fuel tank, fuel line, filter if there is one. Dump the gas into a container so you can see it. Replace it in any event. Blow out any lines you can with compressed air - follow the gas line from the tank to the carb. The fuel shut off could be partially blocked. If you have the wherewithal, take the float bowl off and clean it, and see if the float is free and if it’s pushing the needle up and down when you manually move it. Get some carburetor cleaner and squirt it through whatever passages you can get at to see if they are free.