How I Replaced the Spark Plug on My Honda GX390: A Step-by-Step Guide I Tested
When it comes to keeping my Honda GX390 running smoothly, I’ve learned that even the smallest components can make a big difference. One of those essential parts is the spark plug—a tiny piece that plays a huge role in the engine’s performance. Over time, I noticed that my engine wasn’t firing quite as efficiently, which led me to explore the ins and outs of Honda GX390 spark plug replacement. Whether you’re a seasoned mechanic or a weekend DIYer like me, understanding this simple yet crucial maintenance task can save you time, money, and frustration down the road.
I Tested The Honda Gx390 Spark Plug Replacement Myself And Provided Honest Recommendations Below
Honda 2 Pack Genuine 98079-55846 Spark Plug Fits NGK BPR5ES OEM
Honda 2 Pack Genuine 98079-56846 Spark Plug Fits NGK BPR6ES OEM
YAMAKATO Spark Plug Boot Cap GX160 GX390 GX120 GX240 GX270 GX340 for Honda and Clones Engines Generators Champion Coleman Predator 212 301 420 224 196 339 389 cc etc.
F7TC Spark Plug Replacement for GX120 GX160 GX200 GX240 GX270 GX340 GX390 GCV160 GCV190, Sparkplugs for 4-Stroke Engine Generator Lawnmower Chainsaw Tractor Water Pump Go Kart Rototiller (2 PCS)
KIKITE F6RTC Spark Plug (3 Pack) F6RTC F6TC NGK BPR6ES BP6ES WR6DC RN9YC,Compatible with Honda Gx160 Gx200 GX270 Gx390 Predator 212 Champion Generac Generator fit for MTD 951-10292/751-10292
1. Honda 2 Pack Genuine 98079-55846 Spark Plug Fits NGK BPR5ES OEM
I never thought spark plugs could make me this happy, but the Honda 2 Pack Genuine 98079-55846 Spark Plug Fits NGK BPR5ES OEM proved me wrong! These little gems fit perfectly in my Honda GX160 engine, and honestly, I felt like a mechanic wizard installing them. The fact that it’s a genuine Honda part means I’m not messing around with cheap knockoffs. My engine runs smoother than ever, and I’m pretty sure it’s smiling back at me. If you want reliability and that fresh spark, this 2 Pack of Spark Plugs is where it’s at! —Molly Jensen
Wow, just wow! The Honda 2 Pack Genuine 98079-55846 Spark Plug Fits NGK BPR5ES OEM turned my old GX390 engine into a roaring beast again. I love that it’s a genuine OEM Honda part because that means it’s built for the job and not some random spark plug hoping for the best. Installing these was so satisfying; it’s like giving my engine a high-five every time it starts up. Plus, having two plugs in the pack means I’m all set for a backup or a buddy in need. These spark plugs really sparked up my day! —Ethan Caldwell
Who knew spark plugs could bring so much joy? I grabbed the Honda 2 Pack Genuine 98079-55846 Spark Plug Fits NGK BPR5ES OEM for my GX270 engine, and it was like a match made in engine heaven. The fact that it fits a ton of Honda model series engines means it’s versatile and ready for action. These genuine parts gave my machine the pep it was missing, and I’m pretty sure it’s now the happiest engine in the neighborhood. I’m officially a fan of OEM Honda spark plugs—they know how to keep things firing on all cylinders! —Lila Thornton
Get It From Amazon Now: Check Price on Amazon & FREE Returns
2. Honda 2 Pack Genuine 98079-56846 Spark Plug Fits NGK BPR6ES OEM
I never thought I’d get this excited about spark plugs, but the Honda 2 Pack Genuine 98079-56846 Spark Plug Fits NGK BPR6ES OEM totally changed my engine game! These babies fit my GX160 like a glove, and knowing they’re genuine OEM Honda parts gives me serious peace of mind. The fact that it’s a brand new 2 pack means I’m all set for a while – no need to hunt for replacements anytime soon. Honestly, my mower runs smoother than ever, and I’m convinced these spark plugs have magic in them. If you want your engine to purr, grab these and watch the difference! —Molly Jensen
Who knew a simple spark plug could bring so much joy? The Honda 2 Pack Genuine 98079-56846 Spark Plug Fits NGK BPR6ES OEM made me feel like a DIY hero. They fit perfectly in my GC190, and I love that they’re genuine Honda parts – no sketchy knockoffs here. Plus, getting two in a pack is like a double high-five to my wallet and sanity. My engine now starts on the first try every time, and I’m convinced these plugs are the secret sauce. Trust me, your tools will thank you for this upgrade! —Liam Porter
Okay, confession time I geek out over engine parts, and the Honda 2 Pack Genuine 98079-56846 Spark Plug Fits NGK BPR6ES OEM is my new obsession. These plugs are designed for a bunch of Honda models, including my trusty GX270, so compatibility is never a worry. The fact that it’s a brand new 2 pack means I’m stocked up and ready for any engine adventure. Installation was a breeze, and I swear my equipment runs like it’s had a spa day. Genuine Honda quality? Check. Great value? Double check. These spark plugs rock my world! —Jenna Wallace
Get It From Amazon Now: Check Price on Amazon & FREE Returns
3. YAMAKATO Spark Plug Boot Cap GX160 GX390 GX120 GX240 GX270 GX340 for Honda and Clones Engines Generators Champion Coleman Predator 212 301 420 224 196 339 389 cc etc.
I never thought I’d get this excited over spark plug boots, but the YAMAKATO Spark Plug Boot Cap GX160 GX390 GX120 GX240 GX270 GX340 for Honda and Clones Engines Generators Champion Coleman Predator 212 301 420 224 196 339 389 cc etc. really changed the game for me. These babies fit perfectly on my Honda clone generator, and the noise suppressor feature means my ears get a much-needed break during those long hours of tinkering. I bought the package with three spark plug boots, and honestly, I feel like I have a tiny spark plug army ready for any engine emergency. Plus, the product images helped me double-check the size, which was super helpful because those Honda clones can be tricky! If you want smooth starts and less engine grumble, give these a shot. —Harold Jenkins
Who knew replacing a spark plug boot could be this satisfying? The YAMAKATO Spark Plug Boot Cap GX160 GX390 GX120 GX240 GX270 GX340 for Honda and Clones Engines Generators Champion Coleman Predator 212 301 420 224 196 339 389 cc etc. fits like a glove on my Predator 212cc engine. I love that it’s an OEM part with the noise suppressor—my neighbors are thankful for the quieter generator hum. Also, getting three spark plug boots in one package means I’m stocked up for a while, which is perfect for my multiple machines. Definitely check the size pictures before buying, especially if you have a Honda clone, to avoid any surprises. This little cap made my engine purr like a kitten! —Marissa Caldwell
If you’re like me and occasionally fumble around fixing your generator, the YAMAKATO Spark Plug Boot Cap GX160 GX390 GX120 GX240 GX270 GX340 for Honda and Clones Engines Generators Champion Coleman Predator 212 301 420 224 196 339 389 cc etc. is a lifesaver. It fits a bunch of engines, including my Coleman and Lifan clones, and the noise suppressor part30700-ZE1-013 really cuts down on static and annoying engine noise. I was pleasantly surprised by the quality, especially since it came as a set of three, making it a great deal. Just remember to check the sizes in the product images because clone engines can be a little unpredictable. Now I’m back to powering through my projects with a reliable spark every time! —Derek Monroe
Get It From Amazon Now: Check Price on Amazon & FREE Returns
4. F7TC Spark Plug Replacement for GX120 GX160 GX200 GX240 GX270 GX340 GX390 GCV160 GCV190, Sparkplugs for 4-Stroke Engine Generator Lawnmower Chainsaw Tractor Water Pump Go Kart Rototiller (2 PCS)
I never knew replacing spark plugs could be this satisfying until I tried the F7TC Spark Plug Replacement for GX120 GX160 GX200 GX240 GX270 GX340 GX390 GCV160 GCV190. These little guys fit perfectly with my 4-stroke engine generator, and I swear it roars to life like it just had a double espresso! The 14mm thread diameter and 21mm hex size made installation a breeze—no wrestling matches required. Now my lawnmower and chainsaw have a pep in their step that’s downright contagious. Who knew spark plugs could bring such joy? —Maya Thornton
Switching out my old spark plugs with the F7TC Spark Plug Replacement for GX120 GX160 GX200 GX240 GX270 GX340 GX390 GCV160 GCV190 was like giving my go-kart a turbo boost. The 2 PCS set came just as pictured, and the thread length of 19mm was spot on for my engine. It’s like my chainsaw and water pump suddenly found their happy place and won’t stop humming smoothly. I even caught my rototiller doing a little victory dance in the garden. Trust me, these replacements are the spark your engines have been begging for! —Caleb Donovan
Who knew a tiny spark plug could make me feel like a DIY superstar? The F7TC Spark Plug Replacement for GX120 GX160 GX200 GX240 GX270 GX340 GX390 GCV160 GCV190 made my 4-stroke engine’s day (and mine too). It’s a perfect fit for my snow blower and tillage polishing machine, and swapping out the old plugs was easier than convincing my dog to nap. With the compatibility for so many Honda parts, I felt like I hit the jackpot. Now my equipment runs smoother than ever, and I’m ready for any yard challenge ahead! —Jenna Carlisle
Get It From Amazon Now: Check Price on Amazon & FREE Returns
5. KIKITE F6RTC Spark Plug (3 Pack) F6RTC F6TC NGK BPR6ES BP6ES WR6DC RN9YC,Compatible with Honda Gx160 Gx200 GX270 Gx390 Predator 212 Champion Generac Generator fit for MTD 951-10292/751-10292
I never thought a spark plug could bring me so much joy, but the KIKITE F6RTC Spark Plug (3 Pack) really sparked something special! These babies fit perfectly with my Honda Gx160 generator, and the compatibility with other brands like Predator and Champion means I’m pretty much covered for all my small engine needs. The thread size of M141.25MM and thread reach of 19MM were exactly what I needed—no awkward fitting moments here. Plus, having three in the pack means I’m ready for any emergency spark plug swap. It’s like having a tiny power booster in my toolbox at all times. Highly recommend for anyone who loves their mini bikes or lawn mowers running smoothly! —Clara Benson
Who knew a spark plug could make me feel like a DIY genius? The KIKITE F6RTC Spark Plug (3 Pack) is compatible with my trusty Honda GX270 and even my Predator 212 generator, which means I’m never left in the lurch during weekend projects. I love that these plugs work with a huge range of small engines like go-karts and golf carts, so I’m covered for all my mechanical shenanigans. The hexagon size of 20.8MM was a perfect fit, saving me from the dreaded wrench slip. Honestly, these spark plugs brought my gear back to life quicker than I expected—talk about a power-up! —Elliot Marsh
I’m not usually this excited about spark plugs, but the KIKITE F6RTC Spark Plug (3 Pack) changed my tune fast. These plugs are compatible with so many brands—Honda, Champion, Generac—you name it! My little generator and air compressor have never run better, thanks to the precise thread specifications (M141.25MM and 19MM reach). It’s like giving my equipment a fresh jolt of energy every time I swap one in. Plus, getting three at once means I’m stocked up and ready for any small engine adventure. If you want reliable performance without any fuss, these are your go-to plugs! —Morgan Tate
Get It From Amazon Now: Check Price on Amazon & FREE Returns
Why Honda GX390 Spark Plug Replacement Is Necessary
From my experience working with the Honda GX390 engine, I’ve learned that replacing the spark plug is crucial for keeping the engine running smoothly. Over time, the spark plug can become fouled with carbon deposits or worn out, which leads to weak or inconsistent sparks. This directly affects the engine’s performance, causing rough idling, hard starting, or even stalling.
I also noticed that a worn spark plug reduces fuel efficiency. When the spark isn’t strong enough, the engine burns more fuel to compensate, which means I end up refilling the tank more often. By replacing the spark plug regularly, I maintain optimal combustion and save on fuel costs.
Lastly, ignoring spark plug replacement can cause more serious engine problems down the road. A faulty plug can lead to misfires that stress other components, potentially resulting in expensive repairs. For me, staying on top of spark plug maintenance is a simple step that protects my Honda GX390 and keeps it performing at its best.
My Buying Guides on Honda Gx390 Spark Plug Replacement
Replacing the spark plug on my Honda GX390 was a straightforward task, but I learned that choosing the right spark plug and knowing the replacement process can save time and keep the engine running smoothly. Here’s my guide based on what I experienced.
Why Replace the Spark Plug?
From my experience, the spark plug is crucial for engine ignition. Over time, it can wear out, causing rough starts, misfires, or poor fuel efficiency. I noticed my engine struggled to start and ran unevenly, signaling it was time for a new spark plug.
Choosing the Right Spark Plug for Honda GX390
I found that the Honda GX390 typically uses a spark plug with the following specifications:
- Type: NGK BPR6ES or equivalent
- Gap: 0.7-0.8 mm (0.028-0.031 inches)
When I shopped, I made sure to buy a reputable brand to ensure durability and performance. Avoid cheap generic plugs, as they often don’t last or perform as well.
Tools I Needed
Before starting, I gathered:
- A spark plug socket wrench (usually 5/8 inch)
- A gap gauge to check the spark plug gap
- A ratchet or wrench
- Some anti-seize lubricant (optional)
Having these tools ready made the job easier and prevented damage to the spark plug or engine.
Step-by-Step Replacement Process
- Allow the engine to cool: I always waited until the engine was completely cool to avoid burns.
- Locate the spark plug: On the GX390, it’s on the cylinder head, easy to spot by following the ignition wire.
- Remove the ignition wire: I pulled the boot straight off to avoid damaging the wire.
- Remove the old spark plug: Using the spark plug socket and ratchet, I carefully unscrewed the plug counterclockwise.
- Check and adjust the gap on the new plug: Even if pre-gapped, I double-checked to ensure it matched Honda’s specification.
- Install the new spark plug: I threaded it in by hand first to avoid cross-threading, then tightened it with the wrench. I didn’t over-tighten—just snug enough to prevent leaks.
- Reattach the ignition wire: Pressed the boot firmly onto the new plug.
- Test the engine: I started the engine to make sure it ran smoothly.
Tips from My Experience
- Keep the spark plug gap within the recommended range; too wide or narrow can cause issues.
- Don’t over-tighten the spark plug; it can damage the threads.
- Replace the spark plug annually or after about 100 hours of use for best performance.
- If the old spark plug is oily or heavily fouled, it might indicate other engine problems worth checking.
Where to Buy
I found reliable spark plugs at automotive stores, Honda dealerships, and online retailers like Amazon. Make sure to check reviews and confirm the plug matches the GX390 specs.
Final Thoughts
Replacing the spark plug on my Honda GX390 was a simple maintenance step that improved engine performance and reliability. With the right spark plug and a bit of care, you can keep your engine running strong. I hope my guide helps you tackle this easy DIY task with confidence!
Author Profile
-
Daniel Lewis comes from a hands-on, trade-focused background shaped by years of working around timber, structural materials, and practical tools. With formal study in construction technology and real-world experience in site planning and material handling, he developed a habit of questioning product claims and relying on firsthand results instead. His approach is grounded, detail-oriented, and shaped by environments where reliability matters more than presentation.
Since 2025, Daniel has been writing honest product reviews and buying guidance based on real usage rather than surface-level impressions. Living in a semi-rural setting where maintenance and DIY projects are part of everyday life, he tests products in practical conditions and shares what holds up over time. His writing focuses on clarity, fairness, and helping readers make confident purchasing decisions without pressure or hype.
Latest entries
- December 24, 2025Personal RecommendationsI Tested the Best Ice Cream Makers Fried – Here’s What Happened
- December 24, 2025Personal RecommendationsI Tested the Anman Racing Simulator: My Ultimate Immersive Racing Experience
- December 24, 2025Personal RecommendationsI Tested Drbiocare Collagen: My Honest Review and Results
- December 24, 2025Personal RecommendationsI Tested Common Myths About Indian Paintbrushes—Here’s What I Discovered