Craftsman Lawnmower wont start?

Well, momokins, this is what you should have done with the carburetor. Go to O'Reilly's Auto Parts and buy some SeaFoam or B12. Strip down the carburetor and immerse the carburetor parts in the solution for 24 hours. Reassemble the carburetor and add a cupful of SeaFoam or B12 to the gas tank.

When refitting the carburetor, make sure that all the gaskets are good and not broken and the bolts holding the carburetor to the engine are good and tight. If you are unsure, then use a gasket sealant too. Thoroughly clean the spark-plug and make sure the air filter is clean.

mmalky: 50 years fixing and repairing and diagnosing small and large engine problems.

Take it to the lawnmower service shop near you. I suspect the unit is beyond your expertise to do a complete tune up. This includes the carburetor, fuel system and the shutdown circuit which prevents the spark from reaching the plug.

You may have bad gas, a clogged fuel filter, or a bad plug. All are easy to check. Empty out the gas in the tank and put in fresh, change the spark plug and change the fuel filter. Also check the air filter, it wouldn't hurt to change that also. Sometimes it gets so clogged, that the carburetor can't breath.

I don't know what you did to "clean the carb" but you didn't do a good enough job. You still have a dirty carburetor. It needs to be removed, taken apart, and soaked in a good carb cleaner.