My lawn more starts, runs for just a little and then quits.

You ned 3 things to run an engine; air, fuel and spark. When you start your engine you must have all three but then one fades and the engine dies. Remove the air filter to help insure the air flows more freely and see if that improves the running. If notit is time to start taking apart the carb but we will need all of your engine info to go further.

Yes, That Is A Good Place To Start , Air, Spark , Then Fuel. Remove The Air Filter, Prime If So Equipped, Pull The Rope About 5 Times, And Immediately Remove The Spark Plug. See If The Spark Plug Is "wet" If So You Are Getting Fuel Or Some Liquid.
Try These Steps And Let Us Know.