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Iridium Spark Plugs for Small Engines

Updated: Jan. 28, 2022

Get faster, more reliable starts

iridium spark plugsFamily Handyman
Start your lawnmower, RV or other small engine faster by replacing the copper spark plug with an iridium-enhanced spark plug. This article explains how and why they work better.

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Iridium vs. copper

It’s a fact. A spark always jumps from the sharpest edge of the center electrode. But the edges of copper center electrodes round off quickly, increasing the number of starter rope pulls. Iridium-enhanced spark plugs, long standard on late-model cars and trucks, are now available for lawn and garden equipment and motorsports applications. Iridium has the highest melting point of all the precious metals (4,229 degrees F), so it holds its sharp edge longer. Iridium plugs cost a few bucks more, but they provide faster starts and last much longer than conventional copper plugs. Know when to change spark plugs with these tips.

Sharper Edge, Smaller-Diameter Electrode

Look at the difference between an iridium-enhanced spark plug and a conventional copper plug. The iridium-enhanced center electrode is much smaller (.6 mm vs. 2.5 mm) to concentrate the spark. Plus, it holds a sharp edge longer.