When your Honda GCV160 engine—whether it’s powering a lawnmower, pressure washer, or generator—starts acting up, the spark plug is often the first place to look. A hard-to-start engine can turn routine maintenance into a frustrating chore, especially when you’re counting on that machine to get the job done. Whether you’re cutting the lawn on a Saturday morning or trying to clean the driveway before guests arrive, a misfiring or sluggish engine can throw a wrench in your plans. The good news? In many cases, the fix is simpler than you think—and it starts with choosing the right spark plug.
This comprehensive buying guide is designed to take the guesswork out of selecting the best spark plug for your GCV160 engine. We’ll walk you through everything you need to know, from understanding why your engine is hard to start to identifying the exact spark plug that will restore reliable ignition. You’ll learn how to evaluate key factors like electrode design, heat range, material quality, and compatibility. We’ll also compare different types of spark plugs, highlight common mistakes to avoid, and provide expert-backed recommendations based on real-world performance. Whether you’re a seasoned DIYer or a first-time small engine owner, this guide will equip you with the knowledge to make a smart, confident purchase.
The market for spark plugs is crowded with options, ranging from budget-friendly OEM replacements to high-performance aftermarket models. While it might be tempting to grab the cheapest option at the local hardware store, doing so could cost you more in the long run through poor performance, frequent replacements, or even engine damage. Our goal is to help you cut through the noise and find a spark plug that delivers consistent starts, improved fuel efficiency, and long-term reliability—all without overspending. By the end of this guide, you’ll know exactly what to look for, what to avoid, and which spark plugs are truly worth your investment.
What to Look for When Buying Buying Guide
1. Compatibility with GCV160 Engine
The most critical factor when selecting a spark plug is ensuring it’s compatible with your Honda GCV160 engine. This engine is used in a wide range of equipment, including lawn mowers, pressure washers, and generators, and it has specific requirements for spark plug thread size, reach, and heat range. The OEM (Original Equipment Manufacturer) specification for the GCV160 is typically a 14mm thread diameter, 1/2-inch reach, and a projected nose design. Using a plug with incorrect dimensions can lead to poor seating, thread damage, or improper combustion.
Always cross-reference the part number stamped on your current spark plug or consult your owner’s manual. Common OEM numbers include Honda 98079-56846 (NGK BPR6ES) and 98079-55846 (NGK BPR5ES). While these are the factory standards, many aftermarket brands offer direct replacements. However, not all “compatible” plugs are created equal—some may have subtle differences in electrode gap or material that affect performance. Always verify compatibility using a trusted cross-reference chart or by contacting the manufacturer.
2. Heat Range and Thermal Performance
The heat range of a spark plug determines how well it dissipates heat from the combustion chamber. A plug that runs too hot can cause pre-ignition or detonation, while one that runs too cold may foul due to incomplete combustion. The GCV160 engine typically uses a medium heat range plug, such as the NGK BPR6ES (heat range 6) or BPR5ES (heat range 5), depending on the application and operating conditions.
For most residential uses—like mowing the lawn or occasional pressure washing—a heat range of 5 or 6 is ideal. If your engine is frequently used under heavy load or in hot climates, a slightly hotter plug (lower number) may help prevent fouling. Conversely, if you operate the engine in cooler temperatures or for short durations, a colder plug (higher number) might be better. Choosing the wrong heat range is a common cause of hard starting, especially in cold weather. A plug that doesn’t reach its self-cleaning temperature will accumulate carbon deposits, leading to misfires and difficulty starting.
3. Electrode Material and Design
The material and design of the spark plug’s electrodes play a major role in ignition efficiency and longevity. Traditional copper-core plugs are affordable and offer good conductivity, but they wear out faster due to erosion of the center and ground electrodes. Platinum and iridium plugs, on the other hand, are more durable and maintain a sharper edge over time, resulting in a stronger, more consistent spark.
For the GCV160, iridium plugs like the NGK Iridium IX series are an excellent upgrade. They provide a finer electrode tip, which reduces voltage requirements and improves cold starts. This is especially helpful if your engine has been hard to start in the morning or after sitting for a while. Platinum plugs are a solid middle ground, offering better durability than copper without the premium price of iridium. Avoid cheap, low-quality plugs with thin or poorly machined electrodes—they may save you a few dollars upfront but will likely fail prematurely and cause ongoing starting issues.
4. Gap Size and Adjustability
The spark plug gap—the distance between the center and ground electrodes—must be set correctly for optimal performance. The standard gap for most GCV160 engines is 0.028 to 0.031 inches (0.7 to 0.8 mm). A gap that’s too wide can prevent the spark from jumping, especially in older or weaker ignition systems, while a gap that’s too narrow may produce a weak spark that fails to ignite the fuel-air mixture efficiently.
Many aftermarket plugs come pre-gapped, but it’s always wise to check the gap with a wire-type feeler gauge before installation. Never use a coin or flat gauge on fine-wire electrodes, as this can damage them. If adjustment is needed, gently bend the ground electrode—never the center electrode. Incorrect gapping is a frequent cause of hard starting, particularly after replacing a plug. Even a slight deviation can disrupt ignition timing and reduce engine efficiency.
5. Build Quality and Durability
Not all spark plugs are built to the same standards. High-quality plugs feature precision-machined threads, robust insulator materials, and corrosion-resistant coatings. Look for plugs with a solid copper core, a ribbed insulator to prevent flashover, and a nickel-plated shell to resist rust. These features ensure reliable performance in wet or humid conditions, which is common for outdoor power equipment.
Cheap, no-name brands often cut corners on materials and manufacturing, leading to premature failure. For example, a poorly made insulator may crack under thermal stress, causing a misfire. Similarly, low-grade metals can corrode or warp, making future removal difficult. Investing in a reputable brand may cost a bit more, but it pays off in longevity and reliability. A quality spark plug should last 50 to 100 hours of operation, depending on usage and maintenance.
6. Brand Reputation and Reliability
When it comes to spark plugs, brand matters. Established manufacturers like NGK, Bosch, Denso, and Champion have decades of experience in ignition technology and rigorous quality control processes. NGK, in particular, is the OEM supplier for many Honda engines, including the GCV160, so their plugs are engineered to meet exact specifications.
While off-brand or generic plugs may look similar, they often lack the precision and consistency of name-brand products. Some may even use misleading packaging to appear like premium brands. Stick with trusted names to ensure compatibility, performance, and peace of mind. Reading user reviews and checking for certifications (like ISO 9001) can also help verify a brand’s reliability. Avoid buying spark plugs from unknown online sellers or discount bins—these are often counterfeit or outdated stock.
7. Warranty and Support
A good warranty can be a sign of a manufacturer’s confidence in their product. Most reputable spark plug brands offer a limited warranty against defects in materials and workmanship, typically ranging from 6 months to 2 years. While spark plugs are consumable items, a warranty can protect you from receiving a defective unit right out of the box.
Additionally, consider the availability of customer support. If you have questions about installation, compatibility, or performance, being able to contact a knowledgeable representative can save time and frustration. Brands with strong support networks often provide detailed installation guides, cross-reference tools, and troubleshooting tips on their websites. This level of service is especially valuable for first-time buyers or those working on older equipment.
8. User Reviews and Real-World Performance
User reviews offer invaluable insights into how a spark plug performs in real-world conditions. Look for feedback from owners of the same engine model (GCV160) and similar applications (e.g., lawnmowers, pressure washers). Pay attention to comments about starting ease, idle stability, fuel consumption, and longevity.
While a single review may be anecdotal, patterns in feedback can reveal strengths and weaknesses. For example, if multiple users report that a particular plug resolves hard-starting issues, it’s likely a reliable choice. Conversely, if several reviews mention frequent fouling or premature failure, it’s best to avoid that model. Use review platforms like Amazon, Home Depot, or specialized forums to gather balanced perspectives. Just be cautious of fake or incentivized reviews—look for detailed, honest accounts with photos or specific usage scenarios.
Different Types of Buying Guide
Common Buying Mistakes to Avoid
❌ Mistake: Ignoring the Owner’s Manual Specifications
Why it’s bad: The owner’s manual provides the exact spark plug type, gap, and torque specifications for your GCV160 engine. Ignoring these can lead to using an incompatible plug, incorrect gapping, or over-tightening, all of which can cause hard starting, poor performance, or engine damage.
What to do instead: Always consult your manual before purchasing. If you don’t have it, download it from Honda’s official website or search for your model number online. Cross-reference the recommended plug with aftermarket options to ensure compatibility.
❌ Mistake: Choosing the Cheapest Option Available
Why it’s bad: Ultra-low-cost spark plugs often use inferior materials and lack quality control. They may foul quickly, fail to spark reliably, or even damage the ignition system over time. The savings are short-lived when you’re replacing plugs every few months.
What to do instead: Invest in a mid-range plug from a reputable brand. The extra $3–$5 is worth it for improved reliability and longer service life. Think of it as preventive maintenance—not an expense.
❌ Mistake: Not Checking or Adjusting the Gap
Why it’s bad: Even pre-gapped plugs can be out of specification due to shipping or manufacturing variances. An incorrect gap can prevent the spark from jumping, especially in cold or high-altitude conditions, leading to hard starts and misfires.
What to do instead: Always measure the gap with a wire feeler gauge before installation. Adjust if necessary, but do so gently to avoid damaging the electrodes. Record the correct gap for future reference.
❌ Mistake: Using the Wrong Heat Range
Why it’s bad: A plug that’s too hot can cause pre-ignition, while one that’s too cold won’t burn off carbon deposits. Both scenarios lead to fouling, poor combustion, and difficulty starting—especially in seasonal temperature changes.
What to do instead: Stick to the OEM-recommended heat range (usually BPR5ES or BPR6ES for GCV160). Only consider a different heat range if you’ve confirmed a specific operating issue and consulted a technician.
❌ Mistake: Over-Tightening the Spark Plug
Why it’s bad: Over-tightening can strip the threads in the cylinder head, which is aluminum and relatively soft. This can lead to costly repairs and make future plug changes extremely difficult.
What to do instead: Hand-tighten the plug first, then use a torque wrench to tighten to the manufacturer’s specification (typically 13–18 ft-lbs for small engines). If you don’t have a torque wrench, tighten a quarter-turn after the plug seats.
❌ Mistake: Reusing Old Spark Plugs
Why it’s bad: Spark plugs wear out over time. Reusing an old plug—even if it looks clean—can result in weak sparks, poor fuel economy, and hard starting. Electrode erosion and insulator degradation aren’t always visible.
What to do instead: Replace the spark plug at least once per season or every 50 hours of use. Keep a spare on hand for quick swaps during maintenance.
❌ Mistake: Buying Based on Packaging Alone
Why it’s bad: Flashy packaging and bold claims (“maximum power!” or “instant start!”) don’t guarantee performance. Some brands use misleading marketing to sell low-quality products.
What to do instead: Focus on technical specs, brand reputation, and user reviews. Look for plugs with clear part numbers, material descriptions, and compatibility information.
Budget Guidelines: How Much Should You Spend?
When it comes to spark plugs for the GCV160, 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 standard copper-core plugs, often sold in bulk or as generic replacements. They work fine for occasional use and can resolve basic starting issues. However, they wear out faster and may require more frequent replacement. Best for users on a tight budget or those maintaining older equipment with minimal usage.
Mid-Range ($5 – $10): This is the sweet spot for most GCV160 owners. You’ll find quality platinum or premium copper plugs from reputable brands like NGK, Bosch, or Champion. These offer better durability, more consistent performance, and improved cold starts. Ideal for regular use in lawnmowers, pressure washers, or generators.
Premium ($10 – $15): Iridium and double platinum plugs fall into this category. They provide superior spark efficiency, longer service life (up to 100+ hours), and excellent performance in challenging conditions. Worth the investment if you rely on your equipment frequently or operate in extreme temperatures.
Luxury ($15+): High-performance or racing-grade plugs are overkill for a standard GCV160 unless the engine has been modified. These are designed for high-compression or turbocharged applications and may not perform optimally in a stock small engine. Only consider if you’re tuning for maximum output.
Expert Tips for Getting the Best Deal
Finding the right spark plug at the right price doesn’t have to be a hassle. With a few smart strategies, you can save money and ensure you’re getting a quality product.
1. Buy During Off-Season Sales: Retailers often discount outdoor power equipment parts in late fall or winter, when demand is low. Stock up on spark plugs during these periods for the best deals.
2. Shop at Reputable Retailers: Purchase from trusted sources like Home Depot, Lowe’s, Amazon (sold by the brand or authorized dealer), or small engine specialty shops. Avoid unknown online marketplaces where counterfeit parts are common.
3. Check for Manufacturer Rebates: Some brands offer mail-in rebates or instant discounts on spark plugs, especially during spring maintenance campaigns. Sign up for newsletters to stay informed.
4. Buy in Multi-Packs: If you maintain multiple GCV160-powered tools, consider buying spark plugs in packs of 2 or 4. You’ll save per unit and always have a spare on hand.
5. Read Return Policies: Make sure the seller accepts returns if the plug doesn’t fit or perform as expected. Most reputable retailers offer 30-day return windows.
6. Test Before Committing: If possible, try one plug first before buying a bulk pack. Install it, run the engine, and observe starting performance and idle quality.
7. Use Cross-Reference Tools: Websites like NGK’s or Bosch’s official cross-reference databases let you input your OEM number and find compatible aftermarket options. This ensures you’re getting the right plug without guesswork.
8. Consider Lifetime Cost, Not Just Price: A $12 iridium plug that lasts 100 hours may be a better value than a $3 copper plug that needs replacing every 30 hours. Calculate cost per hour of use to make smarter decisions.
Frequently Asked Questions
Q: Why is my GCV160 engine hard to start?
A: Hard starting in a GCV160 can be caused by several factors, including a fouled or worn spark plug, incorrect gap, wrong heat range, weak ignition coil, or fuel system issues. The spark plug is often the easiest and most common fix—start there before investigating more complex problems.
Q: How often should I replace the spark plug in my GCV160?
A: Honda recommends replacing the spark plug at least once per season or every 50 hours of operation. If you use your equipment heavily or in dirty/dusty conditions, consider replacing it more frequently.
Q: Can I use a different spark plug brand in my GCV160?
A: Yes, as long as it matches the OEM specifications (thread size, reach, heat range, and gap). NGK, Bosch, Denso, and Champion all offer compatible plugs. Just ensure the part number cross-references correctly.
Q: Should I gap my spark plug before installing?
A: Yes. Even if the plug is labeled as pre-gapped, always verify the gap with a wire feeler gauge. The correct gap for most GCV160 engines is 0.028–0.031 inches.
Q: What’s the difference between BPR5ES and BPR6ES?
A: These are NGK part numbers. The “5” and “6” refer to the heat range—BPR5ES runs slightly hotter than BPR6ES. The GCV160 typically uses BPR6ES, but some applications may specify BPR5ES. Check your manual to be sure.
Q: Can a bad spark plug damage my engine?
A: While a faulty spark plug won’t usually cause catastrophic damage, it can lead to poor combustion, reduced fuel efficiency, increased emissions, and excessive carbon buildup. Over time, this can affect engine performance and longevity.
Q: Is it worth upgrading to an iridium spark plug?
A: For most users, yes—especially if you experience hard starts or use your equipment frequently. Iridium plugs provide a stronger, more consistent spark and last significantly longer than copper or platinum plugs.
Q: How do I remove a stuck spark plug?
A: Apply penetrating oil (like PB Blaster) and let it sit for 15–30 minutes. Use a proper spark plug socket and ratchet with a long handle for leverage. Turn counterclockwise slowly and steadily—never force it.
Q: Can I clean and reuse a spark plug?
A: While you can clean a lightly fouled plug with a wire brush or spark plug cleaner, it’s not recommended for long-term reliability. Electrode wear is often invisible, and cleaning can’t restore lost performance. Replacement is the safer choice.
Q: What tools do I need to change a spark plug?
A: You’ll need a spark plug socket (usually 5/8” or 13/16”), a ratchet, an extension bar, a torque wrench (optional but recommended), and a gap tool. Safety gloves and eye protection are also advised.
Our Final Recommendations
Best for Budget-Conscious Buyers: NGK BPR6ES (Copper) – At around $4, this is the OEM-standard plug that delivers reliable performance for occasional use. It’s affordable, widely available, and easy to find at most hardware stores.
Best Overall Value: NGK Iridium IX BPR6ES – Priced around $12, this iridium plug offers superior cold starts, longer life, and consistent performance. It’s the best balance of cost and quality for most GCV160 owners.
Best Premium Option: Bosch Platinum+4 FGR7DQP – At $14–$16, this double-platinum plug features a unique four-electrode design for enhanced durability and improved ignition. Ideal for heavy-duty or frequent use.
Best for Beginners: Champion RA8HC – A simple, reliable copper plug that’s easy to install and widely compatible. Great for first-time users who want a no-fuss solution.
Best for Advanced Users: Denso Iridium Power IW20 – With a fine 0.4mm iridium center electrode, this plug delivers maximum spark efficiency and is perfect for those who want top-tier performance and precision.
Conclusion: Making the Right Choice
Choosing the best spark plug for your GCV160 engine doesn’t have to be complicated—but it does require attention to detail. A hard-to-start engine is often a sign that your spark plug is worn, fouled, or mismatched. By understanding key factors like compatibility, heat range, electrode material, and gap size, you can make an informed decision that restores reliable performance and extends the life of your equipment.
Remember, the cheapest option isn’t always the best value. Investing in a quality spark plug from a trusted brand pays off in easier starts, better fuel efficiency, and fewer maintenance headaches. Whether you’re a weekend warrior or a daily user, prioritize your needs, read the specs, and don’t skip the basics like checking the gap and torque.
With the insights from this guide, you’re now equipped to tackle spark plug selection with confidence. Take the time to choose wisely, install correctly, and maintain regularly—your GCV160 will thank you with smooth, dependable operation season after season.