Are you able to see fuel at the carb inlet? Try plugging the exhaust with your finger and giving it a quick bump with the starter, then move your finger and try.
I see a lot of people not apply any throttle when starting. It's easier to get an engine going if you hold the throttle open a bit more than idle then you can back off once it starts. Don't pump the throttle as that won't do anything, apply 1/4 throttle and hold it there while trying to start.