Hi.
There is gas smell in the carburetor because the engine is not starting and carburetor is flooding.
As first thing ensure that there is spark, pull the spark plug wire and put the end near to engine block while cranking. You will see the spark. If there is no spark, check distribution coil and wires.
If there is spark, check if there is fuel pressure, if there is smell from carb, then the fuel pressure should be Ok.
Once you are sure that the pump is doing its job, and that there is pressure, check the carburetor settings. The mixture is probably too rich or too lean, and for that reason it is not igniting.
If it is not a matter of carburetor settings, then the carb must be taken apart to check carburetor filter.
To get parts and diagrams see:
Outdoor Distributors - Lawn Mower Parts