Small Engines (Lawn Mowers, etc.): MOWER

Question
hello i have a briggs and stratton self propelled mower. the problem im having is my mower wont run. it is getting fire the coil and spark plug is good and my key way and my float... it acts like it wants to run but it just backfires out the carberatur

Answer
Is the blade or blade adapter loose or cracked?  Does the mower try to pull the rope out of your hand when you try and start it?

If you remove the air filter and prime the engine, will it start?  I use an old style dinner ketchup bottle with the pointy/tapered tip for priming engines...just add a little new gas to the bottle and squirt into the carburetor/air filter housing.

Let me know.
Eric