the plug and pull it a few time and see if it will go. You are bypassing the carburetor and sometimes running it that way is enough to get the fuel system to flow. If it runs for 5-10 secs and quits that means you are having fuel, carb or air problems. If it doesn't run at all you might have spark problem.

Also, I use Seafoam with all my two-cylinder engines and the combined age of my mower, edger, and weed-wacker is 61 years and they all run great.