how can i fix my lawn mower? ?

how can i fix my lawn mower= 6.75 hp. briggs and stratton? i have adjusted the spark plug, change the oil, change the gasoline, clean the air filter, clean the throttle with carburetor cleaner, and when i put a little carburetor cleaner inside the throttle it turns on and then it stops. i don't know what is the problem with my lawn mower can you please help if possible. thankyou! sincerely,

john b.
April 2013