Most small engine starting problems can be solved by simply (1) removing the gas (2) turning the screw under the carburetor to drain the sediment bowl, and (3) only using gas without ethanol. The engine should then start with no future problems. You can find which stations sell non-ethanol gas...
You may be overcomplicating a simple problem. (1) Only use gas without ethanol additives (small engines don't like it), (2) find a screw on the bottom of the carburetor to drain what fuel is in the bowl, (3) retighten the screw, and (4) start the mower.