A hard-starting push lawn mower troubles a good number of gardeners. The majority of them have simple hand-pulled rope starters, and although some improvements have been made to make them start easier, pulling a starting rope 10 or 20 times to start a lawn mower is difficult. However, there are a few simple tips and techniques that will aid anyone when they are trying to start their lawn mower, and using them will cut preparation time down dramatically.
Change the spark plug at the beginning of every season. Spark plugs are inexpensive; at the beginning of the mowing year the small cost will save you time and frustration.
Use fresh gasoline. Gasoline sitting more than 3 months is old and needs to be recycled at the local service station. Don't stock up on gasoline; get what you'll need for a few cuttings worth, use it up, and then get some more.
Push your throttle lever into the "choke" position.
Prime the carburetor. On newer lawn mowers there will be a button primer that feeds gas directly into the carburetor. Most engines will be sufficiently primed after two or three squirts. However, older models don't have this feature. To prime these, after the throttle is in "choke", slowly but firmly pull the rope starter just enough to make the piston in the engine move. Do this two or three times and you will feed gasoline into the carburetor in the exact same way that a button primer does.
Pull the starter rope with force after priming and the mower should start on the first pull. If it doesn't start it will have at least coughed, meaning there was partial ignition in the cylinder. If it coughs one time, it will usually start the next time.