Continuously stalling and extreme difficulty restarting.

The brass "Bolt" that holds the "cup" on the bottom of your carburetor is also the main fuel metering jet for the engine. Get yourself a can of automotive carb cleaner, the aerosol type that comes with the small red plastic tube on the side of the can. Remove the "Bolt" and "cup". (Tip: tilt the carb side of the mower UP about 45 degrees and support it with whatever you have, wood, bricks etc. This will help stem the flow of gas from the tank while you have the "cup" removed.) Examine the "Bolt" and you will see one or two small holes in the side of the "Bolt" between the hex head and the threads. These are the metering orifices. Use the carb cleaner to throughly clean the "Bolt" orifices. (Tip: DO NOT attempt to 'drill' the orifices clean) Next, use the red plastic tube to spray carb cleaner up through the hole on the carburetor that the "Bolt" screws into. Be liberal with the cleaner. Finally, clean the "cup" with the spray one more time for good measure. Put everything back together. (Tip: easy does it on tightining the "Bolt") Level the mower, check for leaks and verify the oil level is OK. If the plug and air filter are up to snuff you should be good to go. (Tip: how old is your fuel? You should keep it around for only about 30 days unless you use fuel stabilizer. These little engines LOVE fresh fuel) Good Luck.