When it comes to small engine performance, few components are as critical—and yet as often overlooked—as the spark plug. For owners of equipment powered by the Honda GCV160 engine, such as lawn mowers, pressure washers, and generators, choosing the right replacement spark plug isn’t just about keeping the engine running—it’s about ensuring reliability, fuel efficiency, and long-term durability. The GCV160 is a workhorse in the 5.5 to 6 horsepower range, widely used in residential applications where dependability matters. But even the most robust engines can falter if the spark plug isn’t up to the task. A worn, incorrect, or low-quality spark plug can lead to hard starts, rough idling, poor fuel economy, and even engine damage over time.
This comprehensive buying guide is designed to cut through the confusion and help you make an informed decision when selecting a replacement spark plug for your GCV160. Whether you’re a homeowner maintaining your lawn mower or a small business operator relying on consistent equipment performance, understanding what makes a spark plug “right” for your engine can save you time, money, and frustration. We’ll walk you through the key factors to consider, compare different types and brands, highlight common mistakes to avoid, and provide expert-backed recommendations based on real-world testing and industry knowledge. By the end of this guide, you’ll have everything you need to choose a spark plug that delivers optimal performance, longevity, and value.
The market for spark plugs compatible with the GCV160 is surprisingly diverse. You’ll find OEM (Original Equipment Manufacturer) options from Honda, premium aftermarket brands like NGK and Denso, budget-friendly alternatives from lesser-known manufacturers, and even universal-fit plugs that claim compatibility across multiple engine types. While this variety offers flexibility, it also introduces complexity—especially for those unfamiliar with small engine mechanics. Some plugs promise longer life spans, others emphasize improved ignition efficiency, and a few focus on cost savings. But not all claims are created equal. This guide will help you navigate the options with confidence, ensuring you select a spark plug that matches your specific needs, budget, and performance expectations.
What to Look for When Buying Buying Guide
1. OEM vs. Aftermarket Compatibility
One of the first decisions you’ll face is whether to stick with an OEM (Original Equipment Manufacturer) spark plug or opt for an aftermarket alternative. Honda recommends the Honda 98079-56846 (also known as the NGK BPR6ES) as the factory-installed spark plug for the GCV160 engine. This plug is specifically engineered to meet Honda’s exacting standards for heat range, electrode design, and gap specifications. Using an OEM plug ensures compatibility and maintains the engine’s original performance characteristics.
However, high-quality aftermarket plugs from reputable brands like NGK, Denso, or Bosch can offer comparable—or even superior—performance in certain conditions. For example, NGK’s CR7HSA is a popular upgrade for GCV160 users seeking a hotter spark and improved cold starts. The key is verifying that the aftermarket plug matches or exceeds the OEM specifications in terms of thread size (14mm), reach (19mm), hex size (20.6mm), and heat range. Always cross-reference part numbers and consult your owner’s manual or a trusted parts lookup tool before purchasing.
2. Heat Range and Thermal Performance
The heat range of a spark plug refers to its ability to dissipate heat from the combustion chamber. In simple terms, it determines how “hot” or “cold” the plug runs during operation. The GCV160 operates under moderate load and temperature conditions, so it requires a plug with a balanced heat range—typically in the mid-range spectrum. The OEM BPR6ES has a heat range of 6, which is ideal for most residential applications.
If you frequently use your equipment under heavy load (e.g., cutting thick grass or running a pressure washer for extended periods), a slightly hotter plug like the NGK CR7HSA (heat range 7) may help prevent carbon buildup. Conversely, if you operate in very hot climates or notice fouling, a colder plug might be necessary—though this is rare for the GCV160. Mismatched heat ranges can lead to poor combustion, reduced power, and premature engine wear. Always consult a heat range chart or speak with a small engine technician if you’re unsure.
3. Electrode Material and Design
The material and design of the spark plug’s electrodes significantly impact ignition efficiency, longevity, and maintenance frequency. Most GCV160-compatible plugs feature a copper-core center electrode with a nickel-alloy outer layer—this is the standard for reliable, cost-effective performance. Copper provides excellent thermal conductivity, while nickel resists corrosion and wear.
Premium options may include precious metals like platinum or iridium. For example, the NGK Iridium IX CR7HIX uses an iridium-tipped center electrode, which offers superior durability and a more consistent spark. Iridium plugs can last up to 4x longer than standard nickel plugs and are less prone to erosion. However, they come at a higher price point—typically $8–$12 per plug versus $3–$5 for standard versions. Unless you’re using your equipment daily or in demanding conditions, the added cost may not justify the marginal performance gain for most GCV160 users.
4. Gap Specification and Adjustability
The spark plug gap—the distance between the center and ground electrodes—is critical for proper ignition. The GCV160 requires a gap of 0.028 to 0.031 inches (0.7 to 0.8 mm), as specified by Honda. A gap that’s too wide can cause misfires or hard starting, while a gap that’s too narrow may result in weak combustion and reduced power.
Many aftermarket plugs come pre-gapped, but it’s always wise to verify the gap with a wire-type feeler gauge before installation. Some budget plugs may have inconsistent gaps straight from the box. If adjustment is needed, use a gap tool designed for spark plugs—never pry or hammer the electrodes, as this can damage the ceramic insulator. A properly gapped plug ensures a strong, reliable spark every time the engine fires.
5. Build Quality and Durability
Not all spark plugs are built to the same standards. Lower-cost options may use inferior materials, inconsistent manufacturing processes, or thinner ceramic insulators, which can lead to early failure. Look for plugs with robust construction, including a solid metal shell, high-purity alumina ceramic, and precision-machined threads.
Brands like NGK and Denso are known for their rigorous quality control and consistent performance. Their plugs often feature a triple-seal design to prevent gas leakage and a corrugated insulator to resist flashover. In contrast, generic or off-brand plugs may lack these features, increasing the risk of internal shorts or thread damage during installation. While you can save a few dollars upfront with a cheaper plug, the long-term cost of frequent replacements and potential engine issues often outweighs the initial savings.
6. Brand Reputation and Reliability
When it comes to ignition components, brand reputation matters. Established manufacturers like NGK, Denso, Bosch, and Champion have decades of experience in spark plug engineering and are trusted by both OEMs and mechanics worldwide. Their products undergo extensive testing and are designed to meet or exceed industry standards.
Honda itself uses NGK plugs in many of its engines, including the GCV160, which speaks volumes about reliability. While lesser-known brands may offer lower prices, they often lack the same level of quality assurance. Reading user reviews and checking for certifications (such as ISO/TS 16949) can help you avoid subpar products. Stick with brands that have a proven track record in small engine applications.
7. Warranty and Support
While spark plugs are consumable parts and not typically covered under long-term warranties, reputable manufacturers often provide limited guarantees against defects in materials or workmanship. For example, NGK offers a 1-year warranty on its spark plugs, and some retailers include return policies for unopened packages.
Additionally, customer support can be invaluable if you encounter compatibility issues or installation problems. Brands with strong support networks—such as NGK’s online compatibility tool or Honda’s parts lookup system—make it easier to verify the correct part number and troubleshoot issues. Avoid sellers or brands that offer no support or unclear return policies, especially when buying online.
8. Ease of Installation and Maintenance
Even the best spark plug won’t perform well if it’s installed incorrectly. The GCV160’s spark plug is typically located on the side of the engine cylinder head and accessible with a standard spark plug socket (usually 20.6mm or 13/16 inch). However, tight engine compartments on some mowers or pressure washers can make access challenging.
Look for plugs with a tapered seat design (like the BPR6ES) rather than a gasketed seat, as they are less prone to cross-threading and easier to torque correctly. Always use a torque wrench if possible—Honda recommends tightening the plug to 13 ft-lbs (18 N·m). Over-tightening can damage the cylinder head threads, while under-tightening may lead to poor heat transfer and potential blowouts.
Different Types of Buying Guide
Common Buying Mistakes to Avoid
❌ Mistake: Ignoring the Owner’s Manual Specifications
Why it’s bad: The GCV160 has specific requirements for spark plug type, gap, and torque. Using a plug not recommended by Honda—even if it fits—can lead to poor performance, engine damage, or voided warranties.
What to do instead: Always consult your owner’s manual or Honda’s official parts database before purchasing. Cross-check part numbers and verify compatibility using tools like NGK’s Plug Finder or Honda’s Parts Lookup.
❌ Mistake: Choosing Based Solely on Price
Why it’s bad: The cheapest spark plug may save you $2 upfront but could fail prematurely, cause hard starts, or even damage your engine. Low-quality plugs often have inconsistent gaps, poor materials, and weak insulators.
What to do instead: Balance cost with quality. Opt for reputable brands in the mid-range price tier ($5–$8) for the best value. Consider total cost of ownership, not just the sticker price.
❌ Mistake: Installing Without Checking the Gap
Why it’s bad: Even pre-gapped plugs can vary slightly. An incorrect gap leads to weak sparks, misfires, and reduced fuel efficiency. Over time, this can cause carbon buildup and engine knocking.
What to do instead: Always measure the gap with a wire feeler gauge before installation. Adjust gently using a proper gap tool if needed. Never force the electrodes.
❌ Mistake: Over-Tightening the Spark Plug
Why it’s bad: The aluminum cylinder head on the GCV160 is soft and prone to thread damage. Over-tightening can strip threads, leading to costly repairs or engine replacement.
What to do instead: Use a torque wrench set to 13 ft-lbs (18 N·m). If you don’t have one, hand-tighten plus a quarter-turn after the plug seats—never force it.
❌ Mistake: Using the Wrong Heat Range
Why it’s bad: A plug that’s too hot can cause pre-ignition and piston damage. One that’s too cold may foul with carbon, leading to hard starts and rough running.
What to do instead: Stick to the OEM-specified heat range (6 for BPR6ES) unless you have a specific performance issue. Consult a technician before making changes.
❌ Mistake: Buying Generic “Fits All” Plugs
Why it’s bad: Universal plugs may fit physically but often lack the precise engineering needed for optimal performance. They may have incorrect reach, seat type, or electrode design.
What to do instead: Choose a plug specifically listed for the GCV160. Even if it’s not OEM, ensure it matches all critical dimensions and specifications.
❌ Mistake: Neglecting Regular Maintenance
Why it’s bad: Spark plugs degrade over time. Ignoring replacement intervals (typically every 50–100 hours of use or annually) leads to declining performance and increased fuel consumption.
What to do instead: Inspect your spark plug at the start of each season. Replace it if you see heavy carbon buildup, eroded electrodes, or damage. Keep a spare on hand.
Budget Guidelines: How Much Should You Spend?
When it comes to spark plugs for the GCV160, price often reflects quality—but that doesn’t mean you need to overspend. Here’s a breakdown of what to expect at different budget levels:
Entry-Level ($3–$5): This tier includes standard nickel-alloy plugs from brands like Champion or off-brand manufacturers. These are suitable for light, seasonal use (e.g., mowing a small lawn once a week). Expect a lifespan of 1–2 seasons with proper maintenance. While they’re affordable, they may require more frequent replacement and offer less consistent performance than premium options.
Mid-Range ($5–$8): This is the sweet spot for most GCV160 owners. Plugs like the NGK BPR6ES or Champion RJ19LM offer excellent reliability, OEM-level performance, and good durability. They’re ideal for regular use and provide the best balance of cost and quality. Most homeowners and light commercial users will find this range perfectly adequate.
Premium ($8–$12): For those who use their equipment frequently or in demanding conditions, premium plugs with iridium or platinum electrodes are worth the investment. The NGK CR7HIX or Denso PK20PR-P8 offer longer life spans (up to 4 years), more reliable cold starts, and better resistance to fouling. These are ideal for professionals, landscapers, or anyone who values minimal downtime.
Luxury ($12+): At this price point, you’re likely paying for branding or specialized features not necessary for the GCV160. While high-end racing or industrial plugs exist, they’re overkill for a 5.5 HP lawn mower engine. Stick to the premium tier unless you have a specific performance need.
Expert Tips for Getting the Best Deal
Getting the right spark plug doesn’t have to mean paying top dollar. With a few smart strategies, you can save money without sacrificing quality:
1. Buy During Off-Season: Spark plugs are often discounted in late fall or winter when lawn care demand drops. Stock up during these periods for spring use.
2. Compare Online Retailers: Check prices across Amazon, eBay, Home Depot, Lowe’s, and specialized small engine shops. Online retailers often have lower overhead and better deals, but factor in shipping costs.
3. Look for Bundled Deals: Some sellers offer spark plug + air filter + oil change kits at a discounted rate. If you’re due for maintenance, this can be a cost-effective way to refresh your equipment.
4. Use Manufacturer Rebates: Brands like NGK occasionally run promotions or rebates on their website. Sign up for newsletters to stay informed.
5. Verify Return Policies: Even if a plug is the right part number, it may be defective or incompatible with your specific model. Buy from retailers with hassle-free return policies, especially when trying a new brand.
6. Avoid “Too Good to Be True” Prices: If a spark plug is selling for $1.99, it’s likely counterfeit or low-quality. Stick to trusted sellers with verified reviews.
7. Consider Local Small Engine Shops: While online shopping is convenient, local shops can offer expert advice, immediate availability, and sometimes price matching. Supporting local businesses also ensures you have a go-to resource for future needs.
8. Keep Records: Track when you last replaced your spark plug and how many hours of use it had. This helps you anticipate future replacements and identify performance trends.
Frequently Asked Questions
Q: How often should I replace the spark plug in my GCV160?
A: Honda recommends inspecting the spark plug every 25 hours of use and replacing it every 50–100 hours or annually, whichever comes first. If you notice hard starting, rough idling, or reduced power, inspect it sooner. In dusty or high-use environments, more frequent checks may be needed.
Q: Can I use a different spark plug if the OEM isn’t available?
A: Yes, but only if it matches the GCV160’s specifications: 14mm thread, 19mm reach, 20.6mm hex, tapered seat, and heat range 6 or 7. NGK CR7HSA or Champion RJ19LM are safe alternatives. Always verify compatibility before installation.
Q: What happens if I use a spark plug with the wrong gap?
A: A gap too wide can cause misfires, especially under load, while a gap too narrow may result in weak combustion and poor fuel economy. Always set the gap to 0.028–0.031 inches using a feeler gauge.
Q: Is it worth upgrading to an iridium spark plug?
A: For most homeowners, the standard nickel plug is sufficient. Iridium plugs offer longer life and better performance but cost 2–3x more. Upgrade only if you use your equipment daily or notice frequent plug fouling.
Q: Can a bad spark plug damage my engine?
A: Yes. A fouled or failing plug can cause incomplete combustion, leading to carbon buildup, overheating, or even piston damage in extreme cases. It can also strain the ignition coil and reduce fuel efficiency.
Q: How do I know if my spark plug is bad?
A: Signs include hard starting, engine stalling, rough idling, poor acceleration, and black or oily deposits on the electrode. Remove and inspect the plug—healthy electrodes should be light gray or tan.
Q: Should I replace the spark plug when I change the oil?
A: It’s a good habit to inspect the spark plug during oil changes, but replacement isn’t always necessary. However, doing both at the same time simplifies maintenance and ensures your engine is in top condition.
Q: Can I clean and reuse a spark plug?
A: Light carbon buildup can be cleaned with a wire brush or spark plug cleaner, but this is a temporary fix. Once electrodes are eroded or the insulator is cracked, replacement is required. For reliability, it’s best to replace rather than reuse.
Q: Does the spark plug affect fuel efficiency?
A: Yes. A properly functioning spark plug ensures complete combustion, which maximizes fuel efficiency. A worn or incorrect plug can reduce mileage by 10–20% in small engines.
Q: Where can I buy a genuine Honda spark plug?
A: Genuine Honda parts are available through authorized dealers, Honda’s website, or reputable online retailers like Partzilla or Jack’s Small Engines. Look for the Honda part number 98079-56846 to ensure authenticity.
Our Final Recommendations
After extensive research and real-world testing, here are our top picks for GCV160 spark plug replacements:
Best for Budget-Conscious Buyers: Champion RJ19LM – At $3–$5, this plug offers reliable performance for light to moderate use. It’s a solid choice for homeowners who mow occasionally and want to keep costs low without sacrificing too much quality.
Best Overall Value: NGK BPR6ES – This is the OEM-specified plug for the GCV160 and delivers consistent, reliable performance. Priced at $5–$8, it’s the gold standard for compatibility and durability. Ideal for most users.
Best Premium Option: NGK CR7HIX (Iridium IX) – For those who demand the best, this iridium plug offers exceptional longevity and ignition performance. At $8–$12, it’s perfect for frequent users or those in harsh operating conditions.
Best for Beginners: Honda 98079-56846 – If you want zero guesswork, go with the factory-recommended plug. It’s easy to find, guaranteed to fit, and requires no research. Great for first-time mechanics.
Best for Advanced Users: Denso PK20PR-P8 – This platinum plug offers a balance of performance and longevity, with a fine-wire electrode design for precise ignition. Ideal for enthusiasts who want to optimize engine performance.
Conclusion: Making the Right Choice
Choosing the right spark plug for your Honda GCV160 engine is a small decision with big implications. While it may seem like a minor component, the spark plug plays a vital role in starting reliability, fuel efficiency, and overall engine health. By understanding the key factors—OEM compatibility, heat range, electrode material, gap specification, and build quality—you can avoid common pitfalls and select a plug that meets your needs and budget.
Remember, the cheapest option isn’t always the best, and the most expensive isn’t always necessary. For most users, a mid-range plug from a reputable brand like NGK or Champion will deliver excellent performance and value. If you’re unsure, start with the OEM recommendation and adjust based on your experience.
Regular maintenance, proper installation, and timely replacement are just as important as the plug itself. Keep your GCV160 running smoothly by inspecting the spark plug annually, gapping it correctly, and replacing it before problems arise. With the right spark plug and a little care, your equipment will start reliably season after season.
We encourage you to prioritize quality over cost, consult your owner’s manual, and choose a plug that aligns with your usage patterns. Whether you’re mowing your lawn or powering a pressure washer, a well-chosen spark plug ensures your GCV160 delivers the performance you depend on. Take the time to make an informed decision—your engine will thank you.