16/10/2026
【Mower won’t start. The spark plug looks rusty. Do you need a new one?】
Maybe. But the rust in this photo is on the outside of the plug. To find out more, you need to look at the tip.
Let the engine cool, disconnect the plug wire, and take the plug out:
• Ceramic cracked or electrode badly worn? Replace it with the plug specified for your engine.
• Dry black soot on the tip? Check the air filter and choke too. Otherwise, the new plug could get dirty again.
• Tip wet with fuel after several starting attempts? Check the starting procedure and ignition before buying another plug.
That rusty outside is a reason to take a closer look. It isn’t enough to diagnose the no-start on its own.
Need Help with Repairing? HIPA Works.