Craftsman 675 series 190 cc lawn mower Wont start

Take air cleaner off. Shoot some spray carburetor cleaner in the carburetor and try to start Try this a few times to see if the engine will fire.. If it fires or starts then there is a fuel delivery problem. Could be a dirty fuel filter, bad (stale) gas, a dirty carburetor. If it does not start with the carb cleaner, check the spark plug. It may be fouled. Check for spark - take plug out of head. with the plug attached to plug wire, hold plug with a pair of insulated pliers, and touch outside of plug where the threads are to the engine, while some one pulls on the start cord. You should get a bluish spark. If you get a weak spark use a new plug and try again. There should be a bluish spark. Make sure you hold the plug against the engine making good contact. If no spark at all, could a bad magneto.

Getting back to the carburetor. If you think the gas in the tank is stale, drain it out and put fresh gas in the tank. Change the gas filter.
The arburator may be cleaned by pouring a 1/2 can of fuel system cleaner in the gas tank and spraying the spray cleaner down the carburetor throat.