YAMAKATO 698369 Air Filter with Spark Plug Set Lawn Mower 3.0-5.0 HP Gross HP/CV, 4.50-6.00 Gross Torque, 450-600 Series, 5088

What It Is

This is a two-piece replacement kit containing an air filter and spark plug for small engines in the 3.0–5.0 HP range, such as those on walk-behind lawn mowers, log splitters, and pressure washers. It’s designed for engines using the common 450–600 series filter style and a standard 14mm spark plug.

Fitment & Compatibility

Before buying, confirm your engine’s gross torque falls between 4.50–6.00 ft-lb and that it’s a 450–600 series air filter housing. This set is aftermarket, not OEM, so it won’t match every brand’s part number exactly—but it’s a direct fit for many Briggs & Stratton, Tecumseh, and MTD engines from the 1990s onward. Measure your old filter’s height and width (roughly 2.5” x 3.5”) and check that the spark plug has a 14mm thread diameter with a 3/4” reach. If your mower uses a smaller or different plug type (e.g., 18mm or short-reach), this won’t work.

Key Things to Know

• Quality: The filter is foam-and-paper hybrid; it’s adequate for seasonal mowing but not heavy-duty commercial use. The spark plug is pre-gapped, but always verify gap with a feeler gauge (recommended 0.030”) before installation.
• Installation: Easy—remove the old filter cover, swap the plug with a 5/8” socket, and replace the filter. No special tools needed.
• Common gotchas: The spark plug may be a bit snug in some older engine heads; hand-thread first to avoid cross-threading. The filter fits most standard boxes, but check your air filter housing for warping or debris that could prevent a seal.
• Value: At ~$8.88, it’s cheaper than buying filter and plug separately, but the plug may not last as long as a premium brand (e.g., NGK or Champion).

Should You Buy It

Buy it if you need a quick, budget-friendly refresh for a small engine mower or a backup machine and you’ve confirmed the 450–600 series filter and 14mm plug fit your model. Skip it if you run a commercial mower, want long plug life, or have a non-standard engine (e.g., Honda or Kawasaki)—in those cases, stick with OEM parts.