Best to have somebody check for spark at the plug! Those engines that get a lot of use, or are old, usually have the ignition coil go bad. A new coil will usually suffice to get it running again, although a new spark plug will help also.
But, a dirty carburetor, from sitting with fuel in it, or an air filter that is dirty, can also keep it from starting. I'm not familiar with that model, but a carburetor overhaul might help, too.
Better seek professional help! Don't start throwing parts at it--you will spend a lot of money and might still not get it running!