Why won't my engine start, and how do I troubleshoot it?

Common causes for the engine failing to start include the ignition switch being in the OFF position, a disconnected or faulty spark plug wire, the safety key not being fully inserted, the choke not being in the START position, or old/stale fuel in the tank. Additional causes include a flooded engine, an unprimed engine, or a blocked fuel line or fuel shut-off valve in the OFF position. Remedies include repositioning the choke, inserting the key, priming the engine, or draining and replacing stale fuel — noting that fuel can become stale after as little as 30 days. (Page 24)