Replacing everything without knowing what's wrong can get expensive. Does it have spark?
If it's flooding out you can pull plug and dry out the plug, slowing pull the starter rope a few times. Reinsert the plug and try it again. Or open the choke, with full throttle, pull on the pull rope until it cranks. If any time during all that pulling, it tries to crank, more than likely you're getting spark. And no need to change the coil. And that only leaves the carburetor as the culprit.
Did you check the compression? It's a good idea, when you remove the spark plug, to look into the cylinder, with the piston down all the way, and see if anything is scored. Also remove the muffler and look to see if there's anything scored, or any of the ports are clogged. With the muffler off, also check to see if the muffler screen is clogged.