If you’re dealing with a Honda HRX217 lawn mower that’s leaking gas and running rough, chances are your spark plug is either fouled, worn out, or improperly installed—and it’s time for a replacement. While it might seem like a small component, the spark plug plays a critical role in your mower’s performance, fuel efficiency, and overall reliability. A failing spark plug can cause hard starts, misfires, poor acceleration, and yes—even fuel leaks due to incomplete combustion or pressure imbalances in the combustion chamber. Ignoring this issue not only leads to frustrating mowing sessions but can also cause long-term damage to your engine.
This comprehensive buying guide is designed to help you navigate the often-overwhelming world of spark plugs for small engines, specifically tailored for the Honda HRX217 model. Whether you’re a seasoned DIYer or a first-time lawn mower owner, you’ll learn exactly what to look for when purchasing a replacement spark plug, where to buy it, how to avoid common pitfalls, and how to ensure you’re getting the best value for your money. We’ll break down technical specifications, compare top brands, explain pricing tiers, and offer expert tips to help you make an informed decision—so your HRX217 runs smoothly season after season.
The market for small engine spark plugs is surprisingly diverse, with options ranging from budget-friendly OEM replacements to high-performance aftermarket upgrades. However, not all spark plugs are created equal, and using the wrong type—or a low-quality substitute—can lead to more problems down the line. With so many retailers, online marketplaces, and conflicting advice out there, it’s easy to feel overwhelmed. That’s why this guide cuts through the noise. We’ll walk you through every step of the buying process, from understanding your mower’s specific requirements to identifying trustworthy sellers and avoiding counterfeit parts. By the end, you’ll have the knowledge and confidence to choose the right spark plug, install it correctly, and get your Honda HRX217 back in peak condition.
What to Look for When Buying Buying Guide
1. Correct OEM Specifications
When replacing the spark plug on your Honda HRX217, the most important factor is ensuring compatibility with the original equipment manufacturer (OEM) specifications. The HRX217 is powered by a Honda GCV190 engine, which requires a specific spark plug type: typically the Honda 98079-56846 (NGK BPR6ES) or equivalent. This plug features a 14mm thread diameter, 19mm reach, and a 5/8-inch hex size. Using a plug that doesn’t match these dimensions can lead to improper sealing, thread damage, or even engine failure.
Always cross-reference your owner’s manual or the existing spark plug before purchasing. Even slight deviations in thread pitch or reach can cause compression issues or fuel leaks. For example, a plug with too short a reach may not protrude far enough into the combustion chamber, leading to incomplete ignition and carbon buildup. Conversely, a plug that’s too long can strike the piston, causing catastrophic engine damage. Stick to the exact OEM specs unless you’re upgrading for a specific performance reason—and even then, consult a professional.
2. Heat Range Compatibility
The heat range of a spark plug determines how well it dissipates heat from the combustion chamber. A plug that’s too “hot” can cause pre-ignition or detonation, while one that’s too “cold” may foul easily due to carbon buildup. The Honda HRX217’s GCV190 engine is designed to operate optimally with a medium heat range plug—specifically, the BPR6ES, which has a heat rating of 6. This balance ensures reliable cold starts, smooth operation under load, and resistance to fouling during extended mowing sessions.
Choosing a plug with an incorrect heat range can exacerbate issues like gas leakage. For instance, a colder plug may not burn off fuel residues efficiently, leading to wet fouling and potential fuel seepage around the cylinder head. Always verify the heat range matches the OEM recommendation. If you live in an extremely hot or cold climate, consult a Honda technician before deviating from the standard spec, as environmental factors can influence ideal heat range.
3. Electrode Material and Design
Spark plugs come with different electrode materials—most commonly copper, platinum, or iridium—each offering distinct advantages. The OEM BPR6ES uses a copper core with a nickel-alloy electrode, which provides reliable performance and affordability. Copper plugs are excellent conductors and ideal for small engines like the GCV190, but they typically have a shorter lifespan (around 100–200 hours of use).
Platinum and iridium plugs, while more expensive, offer longer service life and improved durability. Iridium, in particular, has a fine wire center electrode that enhances spark efficiency and reduces wear. However, for a residential lawn mower like the HRX217, the performance gains may not justify the higher cost unless you mow frequently or have a large yard. Stick with copper or platinum unless you’re seeking extended maintenance intervals. Avoid cheap, unbranded plugs with inferior electrode materials—they often fail prematurely and can cause misfires.
4. Gap Setting and Adjustability
The spark plug gap—the distance between the center and ground electrode—must be set correctly for optimal combustion. The Honda HRX217 requires a gap of 0.028 to 0.031 inches (0.7 to 0.8 mm). A gap that’s too wide can cause weak or inconsistent sparks, leading to hard starts and poor fuel economy. A gap that’s too narrow may result in incomplete combustion, increasing the risk of fuel buildup and leaks.
Many replacement plugs come pre-gapped, but it’s always wise to verify with a wire-type gap tool. Never use a feeler gauge on fine-wire electrodes, as it can damage them. If adjustment is needed, gently bend the ground electrode—never the center. Pre-gapped plugs from reputable brands like NGK or Denso are usually accurate, but double-checking ensures peace of mind. Incorrect gapping is a common cause of engine performance issues and should never be overlooked.
5. Brand Reputation and Authenticity
Not all spark plugs are created equal, and the market is flooded with counterfeit or low-quality knockoffs—especially on online marketplaces. Stick with trusted brands like NGK, Denso, Bosch, or Honda Genuine Parts. These manufacturers adhere to strict quality control standards and design their plugs to meet or exceed OEM specifications. Counterfeit plugs often use substandard materials, incorrect heat ranges, or flawed electrode designs, which can lead to engine damage, safety hazards, or fire risks.
When shopping online, verify the seller’s reputation. Look for authorized dealers or retailers with high ratings and detailed product descriptions. Avoid listings with stock photos, vague part numbers, or prices that seem too good to be true. A genuine NGK BPR6ES typically costs between $5 and $10—if you see it for $2.99 with free shipping from an unknown seller, it’s likely fake. Authenticity ensures reliability, safety, and compatibility with your HRX217.
6. Warranty and Return Policy
Even high-quality spark plugs can occasionally be defective or incompatible due to manufacturing errors. That’s why it’s essential to purchase from a retailer with a clear warranty and return policy. Most reputable brands offer a limited warranty against defects, but the return window and process vary by seller. For example, Home Depot, Lowe’s, and Amazon typically allow returns within 30 days, while specialized small engine shops may offer longer periods or exchanges.
Before buying, check the return policy—especially if you’re ordering online. Ensure the item is returnable if it doesn’t fit or perform as expected. Some sellers charge restocking fees or only offer store credit, so read the fine print. A good return policy not only protects your investment but also gives you confidence in trying a new brand or type. If a seller doesn’t offer returns, consider it a red flag.
7. Ease of Installation and Accessibility
While not directly related to the plug itself, the ease of installation can influence your buying decision. Some spark plugs come with anti-seize compound pre-applied or feature a tapered seat design for easier threading. Others may require a specific socket size or torque specification. The Honda HRX217’s spark plug is located on the side of the engine and is generally accessible, but tight spaces or corroded threads can make removal difficult.
Consider purchasing a spark plug socket (5/8-inch) and a torque wrench if you don’t already own them. Over-tightening can strip threads, while under-tightening can lead to leaks or loose plugs. Some aftermarket plugs come with installation guides or QR codes linking to video tutorials—small conveniences that can save time and frustration. Choose a plug that’s user-friendly, especially if you’re performing the replacement yourself.
8. Environmental and Usage Considerations
Your mowing habits and environment can influence the type of spark plug you should choose. If you mow frequently, in dusty conditions, or with wet grass, you may benefit from a plug with enhanced fouling resistance—such as one with a projected tip or fine-wire electrode. Similarly, if you live in a region with extreme temperatures, a plug with a slightly different heat range might be warranted, though this should be done cautiously and with expert advice.
Additionally, consider eco-friendly options. Some modern plugs are designed for cleaner combustion, reducing emissions and improving fuel efficiency. While the HRX217 is already a relatively efficient mower, using a high-quality plug can further minimize its environmental impact. Avoid plugs with leaded coatings or non-recyclable materials. Choose sustainable, high-performance options that align with your values and usage patterns.
Different Types of Buying Guide
Common Buying Mistakes to Avoid
❌ Mistake: Buying the Wrong Plug Type
Why it’s bad: Using a spark plug that doesn’t match the HRX217’s specifications can lead to engine damage, poor performance, or even safety hazards. For example, a plug with the wrong thread size may not seat properly, causing gas leaks or compression loss.
What to do instead: Always verify the part number (98079-56846 or BPR6ES) and cross-check with your owner’s manual. When in doubt, take the old plug to a parts store for comparison.
❌ Mistake: Ignoring the Gap Setting
Why it’s bad: A misgapped plug can cause misfires, hard starts, and increased fuel consumption. It may also lead to carbon buildup, which can exacerbate gas leakage issues.
What to do instead: Use a wire-type gap tool to measure and adjust the gap to 0.028–0.031 inches before installation. Never assume pre-gapped plugs are accurate.
❌ Mistake: Choosing the Cheapest Option Available
Why it’s bad: Ultra-low-cost plugs are often counterfeit or made with inferior materials. They may fail quickly, cause engine problems, or even pose a fire risk due to poor insulation.
What to do instead: Invest in a reputable brand like NGK or Denso. The small price difference is worth the reliability and peace of mind.
❌ Mistake: Overlooking the Heat Range
Why it’s bad: A plug with an incorrect heat range can foul easily or cause pre-ignition, both of which can lead to fuel leaks and engine damage over time.
What to do instead: Stick with the OEM-recommended heat range (6 for the BPR6ES). Only consider alternatives if advised by a certified technician.
❌ Mistake: Not Checking Seller Authenticity
Why it’s bad: Buying from unverified online sellers increases the risk of receiving counterfeit parts. These may look similar but lack proper certifications and performance standards.
What to do instead: Purchase from authorized dealers, hardware stores, or well-reviewed online retailers. Look for seller ratings, return policies, and detailed product descriptions.
❌ Mistake: Skipping the Torque Specification
Why it’s bad: Over-tightening can strip the cylinder head threads, while under-tightening can cause leaks or loose plugs. Both scenarios can lead to gas seepage and engine failure.
What to do instead: Use a torque wrench set to 13–15 ft-lbs (18–20 Nm) when installing the new plug. If you don’t have one, hand-tighten plus a quarter turn after the plug seats.
❌ Mistake: Reusing Old Spark Plug Wires or Boots
Why it’s bad: Worn or cracked spark plug boots can cause arcing, misfires, and electrical issues. Reusing old components undermines the benefits of a new plug.
What to do instead: Inspect the boot and wire for cracks, brittleness, or corrosion. Replace them if necessary—especially if your mower is more than 5 years old.
Budget Guidelines: How Much Should You Spend?
When it comes to spark plugs for the Honda HRX217, you don’t need to break the bank—but you also shouldn’t go for the absolute cheapest option. Here’s a breakdown of what to expect at different price points:
- Entry-Level ($2–$5): These are typically generic or unbranded plugs, often sold in bulk or on discount marketplaces. While they may fit physically, they often lack quality control, proper heat ranges, or durable materials. Best used only as emergency replacements or for very occasional mowing. Expect shorter lifespan and higher risk of failure.
- Mid-Range ($5–$9): This is the sweet spot for most homeowners. Brands like NGK and Denso offer reliable copper-core plugs in this range, such as the BPR6ES. They meet OEM specs, come pre-gapped, and are widely available. Ideal for regular mowing and long-term reliability.
- Premium ($9–$15): Platinum or iridium plugs from reputable manufacturers fall into this category. They offer longer service life (up to 300+ hours), better performance under load, and improved fuel efficiency. Worth the investment if you mow frequently or have a large lawn.
- Luxury ($15+): These include high-end iridium plugs with advanced electrode designs or specialty coatings. While they offer marginal performance gains, they’re often overkill for a residential mower like the HRX217. Only consider if you’re a performance enthusiast or operate in extreme conditions.
Expert Tips for Getting the Best Deal
- Buy During Off-Season: Lawn mower parts often go on sale in late fall or winter when demand is low. Stock up during these periods to save 10–20% on spark plugs and other maintenance items.
- Shop at Authorized Retailers: Stores like Home Depot, Lowe’s, and Tractor Supply carry genuine NGK and Honda parts. They also offer in-store pickup, which avoids shipping delays and counterfeit risks.
- Check for Bundles: Some retailers sell spark plug kits that include a new plug, air filter, and oil change kit. These bundles often cost less than buying items separately and ensure comprehensive maintenance.
- Use Manufacturer Rebates: Occasionally, NGK or Honda offers mail-in rebates on small engine parts. Check their websites or ask in-store for current promotions.
- Verify Return Policies: Always buy from sellers with flexible return windows. This allows you to test the plug and return it if it doesn’t perform as expected.
- Avoid Third-Party Marketplaces for Critical Parts: While Amazon and eBay can have good deals, they’re also hotspots for counterfeit parts. Stick to “sold by Amazon” or “fulfilled by” trusted sellers.
- Join Lawn Care Forums: Communities like LawnSite or Reddit’s r/lawncare often share deals, reviews, and installation tips. Members frequently post coupon codes or store alerts.
- Consider Multi-Packs for Future Use: If you have multiple mowers or plan to keep your HRX217 for years, buying a 2- or 3-pack of spark plugs can save money and ensure you always have a spare on hand.
Frequently Asked Questions
Q: Can a bad spark plug cause gas to leak from my Honda HRX217?
A: Indirectly, yes. A fouled or malfunctioning spark plug can cause incomplete combustion, leading to fuel buildup in the cylinder. This excess fuel can seep past the piston rings or valves, potentially appearing as a gas leak. Additionally, poor combustion can increase crankcase pressure, forcing fuel vapors out through seals or vents. Replacing the spark plug often resolves these issues.
Q: How often should I replace the spark plug in my HRX217?
A: Honda recommends replacing the spark plug every 100 hours of operation or at least once per mowing season. If you mow frequently or in dusty conditions, consider checking it mid-season for fouling or wear.
Q: Can I clean and reuse a spark plug instead of replacing it?
A: While you can clean a mildly fouled plug with a wire brush or plug cleaner, it’s not recommended for long-term reliability. Electrodes wear over time, and cleaning won’t restore lost performance. For best results, replace it annually.
Q: What’s the difference between NGK BPR6ES and BPR5ES?
A: The BPR6ES has a heat range of 6, while the BPR5ES has a range of 5 (colder). The HRX217 requires the BPR6ES. Using a colder plug like the BPR5ES can lead to fouling and poor performance in normal operating conditions.
Q: Do I need to replace the spark plug wire when changing the plug?
A: Not necessarily, but it’s a good idea if the wire is cracked, brittle, or over 5 years old. A worn wire can cause misfires and reduce the effectiveness of a new plug.
Q: Can I use a platinum or iridium plug in my HRX217?
A: Yes, as long as it matches the OEM specifications (14mm thread, 19mm reach, correct gap). Platinum and iridium plugs are compatible and offer longer life, but ensure the heat range is appropriate.
Q: Where is the best place to buy a spark plug for the HRX217?
A: Authorized dealers like Home Depot, Lowe’s, or Honda Power Equipment dealers are the safest bets. Online, stick to Amazon (sold by Amazon), RockAuto, or Small Engine Warehouse for verified parts.
Q: How do I know if my spark plug is the cause of the gas leak?
A: Check for black, wet deposits on the plug or around the cylinder head. Perform a compression test—low compression may indicate a sealing issue. If the plug is fouled or damaged, replace it and monitor for leaks.
Q: Is it safe to install a spark plug without a torque wrench?
A: While not ideal, you can hand-tighten the plug and then turn it an additional quarter turn after it seats. Over-tightening is a bigger risk than slight under-tightening. Use a torque wrench if possible.
Q: Can I use a spark plug from a different brand if it fits?
A: Yes, as long as it meets the exact OEM specifications (thread size, reach, heat range, gap). NGK, Denso, and Bosch all make compatible plugs, but avoid no-name brands.
Our Final Recommendations
- Best for Budget-Conscious Buyers: NGK BPR6ES – At $5–$9, it offers OEM-level performance at a fraction of the cost of genuine Honda parts. Widely available and reliable.
- Best Overall Value: Denso W20EPR-U (Platinum) – Slightly more expensive but lasts longer and resists fouling. Ideal for homeowners who want fewer replacements.
- Best Premium Option: Bosch WR7DP (Iridium) – Superior spark efficiency and durability. Perfect for frequent mowers or those seeking maximum performance.
- Best for Beginners: Honda Genuine Plug (98079-56846) – Guaranteed fit and peace of mind. Slightly pricier but eliminates guesswork.
- Best for Advanced Users: NGK Ruthenium HX – A high-performance iridium plug with advanced electrode design. Offers improved combustion and longevity for tech-savvy users.
Conclusion: Making the Right Choice
Replacing the spark plug in your Honda HRX217 is a simple yet critical maintenance task that can resolve issues like gas leaks, hard starts, and poor performance. By choosing the right plug—based on OEM specifications, heat range, electrode material, and brand reputation—you ensure your mower runs efficiently and reliably for years to come. Avoid the temptation to cut corners with cheap, unverified parts, and always verify compatibility before purchasing.
Remember, the spark plug is more than just a small component—it’s the heart of your engine’s ignition system. Investing in a quality replacement from a trusted source not only fixes immediate problems but also prevents future headaches. Use the tips, comparisons, and recommendations in this guide to make an informed decision tailored to your needs, budget, and mowing habits.
Whether you’re a weekend warrior or a seasoned landscaper, taking the time to choose the right spark plug is a small step that pays big dividends. So grab your tools, pick up a quality NGK or Denso plug, and get your HRX217 back to cutting clean, running smooth, and leaking nothing but perfectly trimmed grass.