I'm taking a look at my buddies lawn mower to see if I can get it running. I have not tried to start it yet (another Eastern PA Rainy day). He says it will sometimes start but pops and carries on kind of like out of time as he said. Anyhow I did a compression test on the engine to get things started. I got 65 psi. What is a good compression psi for these engines. I'm going to tackle it in the morning.
Remove air filter and replace spark plug. If you turn mower on its side you get oil on air filter and that will foul spark plug. If that don't work look at valve cover on front of engine sometimes they get bent in and don't let vavles work.