Replacement RCJ6Y Spark Plug for Champion Lawn Mower Models

What It Is

This is a direct-replacement RCJ6Y spark plug designed for Champion-branded lawn mower engines. It provides the ignition spark needed to start and run single-cylinder, small-engine mowers, trimmers, and other outdoor power equipment.

Fitment & Compatibility

Before buying, check your owner’s manual or current plug for the Champion “RCJ6Y” designation. This plug fits most Champion engines in walk-behind mowers, but not all—verify your engine model (e.g., 875, 1000, 1500 series) and deck size isn’t a reliable indicator; focus on the engine label. The RCJ6Y is the OEM-equivalent plug for many Champion mowers (e.g., models with 150cc–200cc engines). It has a 14mm thread diameter, 0.375” reach, and a 5/8” hex size. If your current plug has a different number (e.g., RCJ7Y or RJ19LM), this will not cross-match—stick to the exact RCJ6Y spec.

Key Things to Know

• Quality: This is a basic copper-core plug—works fine for standard use, but not as long-lasting as iridium or platinum plugs. Replace every 100 hours or each season.
• Installation: Simple hand-tighten then 1/2 turn with a spark plug wrench. Over-tightening can crack the porcelain. Gap is pre-set, but check it (0.030”) before installing.
• Common gotcha: Some Champion mowers use a longer-reach plug (RCJ7Y). Using this shorter RCJ6Y in those models can cause misfiring or piston damage. Double-check your old plug’s length.
• Brand note: This is a third-party “Replacement” brand, not Champion OEM. It’s functionally identical but may have slightly different heat range—fine for most residential mowing, but not for heavy commercial use.

Should You Buy It

If you have a Champion mower that calls for an RCJ6Y plug and you want a budget-friendly, drop-in replacement for routine maintenance, this works. It’s not a durability upgrade—stick with it for light-to-moderate use. For commercial or high-hour operation, consider an OEM Champion plug or an iridium alternative for longer life.