Lawnmower: Issues with it running.?

Have you cleaned out your suction filter? It could be clogged with stuff. Is your diaphragm in your carburetor intact? If it's broken, that's your problem. Have you reset the rich-lean screws. Tighten them both up and open them one and a quarter turn. I had a tiller that did exactly the same thing. I reset the screws. That cured it. You might have to clean your carburetor out thoroughly if nothing else works. One final solution. Give it to a needy person and buy you another one. Buy another brand, of course. Hope you can resolve the problem rather then go shopping.