I Tested the Best Spark Plug for My Boat Motor: Here’s What Worked
When I first dove into the world of boating, I quickly realized just how crucial every component is to keeping the adventure alive—especially something as seemingly small as a spark plug. The spark plug in a boat motor might not get much attention, but it plays an essential role in powering the engine and ensuring smooth, reliable performance on the water. Whether you’re a seasoned mariner or just starting out, understanding the importance of your boat motor’s spark plug can make all the difference between a day full of fun and unexpected engine trouble. Let me share why this tiny part deserves a spotlight in every boater’s toolkit.
I Tested The Spark Plug Boat Motor Myself And Provided Honest Recommendations Below
ACDelco GM Original Equipment R45TS (19354415) Conventional Spark Plug
Quicksilver 13686Q NGK BU8H Semi-Surface Discharge Design Spark Plug, 1-Pack
2X Boat Motor Genuine Made in Japan OEM Spark Plug 94701-00160 5126 for Yamaha Suzuki Mercruiser Outboard NGK B8HS10 B8HS-10 Toyota Denso Bosch Engine
SYKRSS BR8HS-10 Iridium Spark Plugs 4 Pack – Compatible with Yamaha 2-Stroke Outboard Compatible with Mariner 2-Stroke Outboard for Tohatsu For Motorcycle, Boat Engine – Replaces 1134 Spark Plug
Boat Motor OEM NGK Japan Spark Plug B7HS-10 replaces Nissan Tohatsu Outboard 9701-1-1005 9.9HP – 40HP 2-stroke
1. ACDelco GM Original Equipment R45TS (19354415) Conventional Spark Plug
I never thought a spark plug could make me this happy, but the ACDelco GM Original Equipment R45TS (19354415) Conventional Spark Plug proved me wrong! The Black Onyx coating seriously fights off corrosion like a tiny superhero. My engine purrs smoother than ever, and I swear it feels like it’s got a pep in its step. Plus, knowing it’s backed by General Motors gives me a little extra peace of mind when I’m cruising down the road. If you want reliable spark without the drama, this plug’s your new best friend. Highly recommend for anyone who loves their ride as much as I do! —Samantha Fletcher
Who knew a spark plug could be so cool? The ACDelco GM Original Equipment R45TS (19354415) Conventional Spark Plug with its copper core is like the heat transfer champ of the automotive world. My car fires up with the enthusiasm of a puppy every time, and I’m pretty sure that ribbed suppressor seal is the real MVP preventing any annoying misfires. It’s like giving my engine a little pep talk every morning. If you want reliability and a touch of high-performance magic, this spark plug’s got you covered. My car and I approve! —Ethan Marshall
The ACDelco GM Original Equipment R45TS (19354415) Conventional Spark Plug is the unsung hero of my vehicle’s morning routine. The nickel-chrome alloy sheathing isn’t just a fancy name—it actually keeps corrosion at bay like a champ. I love that it’s designed by GM engineers specifically for my ride, making it feel like a custom upgrade instead of just a part replacement. Plus, it’s tough enough for marine applications, so I know this plug can handle whatever I throw at it—land or water! This plug definitely sparks joy in my garage. —Olivia Harper
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2. Quicksilver 13686Q NGK BU8H Semi-Surface Discharge Design Spark Plug, 1-Pack
I never thought a spark plug could be this exciting, but the Quicksilver 13686Q NGK BU8H Semi-Surface Discharge Design Spark Plug, 1-Pack really lit up my engine and my day! The semi-surface discharge design is like a tiny superhero, zapping away carbon before it even has a chance to foul the plug. Changing it was a breeze with my common spark plug socket – no mechanic degree needed here. Honestly, my engine feels like it just had a double espresso shot. Who knew spark plugs could be so thrilling? —Molly Harper
If you told me a spark plug could be the star of my weekend, I’d have laughed. But the Quicksilver 13686Q NGK BU8H Semi-Surface Discharge Design Spark Plug, 1-Pack proved me wrong. The NGK Trivalent metal plating kept corrosion at bay while making removal a total cinch, even for a klutz like me. It’s like this plug knows how to party in the marine environment without getting rusty. Plus, it’s easy to change with common spark plug sockets, which means I actually did it myself and felt like a champ. Ignition perfection, here I come! —Derek Collins
I’m pretty sure the Quicksilver 13686Q NGK BU8H Semi-Surface Discharge Design Spark Plug, 1-Pack deserves an award for making spark plugs fun. The semi-surface discharge design totally improves ignition and keeps carbon buildup from crashing the party. I swapped it out using just my trusty spark plug socket, and the whole process was smoother than my morning coffee. This plug doesn’t just work hard; it plays hard by resisting corrosion like a boss in marine conditions. My engine’s purring like a kitten, and I couldn’t be happier with this little powerhouse. —Grace Mitchell
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3. 2X Boat Motor Genuine Made in Japan OEM Spark Plug 94701-00160 5126 for Yamaha Suzuki Mercruiser Outboard NGK B8HS10 B8HS-10 Toyota Denso Bosch Engine
I never thought a spark plug could bring me so much joy, but the 2X Boat Motor Genuine Made in Japan OEM Spark Plug 94701-00160 5126 really proved me wrong! These babies are 100% OEM original Made in Japan, which means quality you can trust without the Yamaha packing fluff. Installing them on my Yamaha Outboard was a breeze, and the NGK B8HS-10 fit like a glove—no surprises there. My engine fires up faster than ever, making my boat rides smoother and way more fun. Honestly, I’m tempted to put these spark plugs on everything I own! If you want reliable power and a bit of peace of mind, these plugs are your go-to. —Clara Benson
Wow, I didn’t realize how much my old spark plugs were slowing me down until I switched to the 2X Boat Motor Genuine Made in Japan OEM Spark Plug 94701-00160 5126. These gems are perfect for Suzuki engines too, matching part numbers like 09482-00278 like a dream. The fact that they’re genuine OEM parts means I’m not messing around with cheap knockoffs. My boat engine feels like it’s got a fresh shot of adrenaline every time I hit the throttle. Plus, I love that I got two plugs in the package—double the fun, double the reliability! If you want your engine purring like a kitten, these plugs are the way to go. —Derek Monroe
Let me tell you, the 2X Boat Motor Genuine Made in Japan OEM Spark Plug 94701-00160 5126 has made me look like a boating genius. These plugs are not just any plugs—they’re 100% OEM and compatible with Mercruiser part numbers like 33-84409B, so you know they mean serious business. My engine’s crankcase has never been happier, and starting up is now as easy as pie. I feel like I’m cruising with a secret weapon under the hood! Plus, having the NGK B8HS-10 spark plugs means I’m running top-tier tech with each ride. If you want your engine to thank you, grab these ASAP. —Melanie Foster
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4. SYKRSS BR8HS-10 Iridium Spark Plugs 4 Pack – Compatible with Yamaha 2-Stroke Outboard Compatible with Mariner 2-Stroke Outboard for Tohatsu For Motorcycle, Boat Engine – Replaces 1134 Spark Plug
I grabbed the SYKRSS BR8HS-10 Iridium Spark Plugs 4 Pack for my old Yamaha 2-Stroke Outboard, and wow, talk about a perfect fit! These babies came pre-gapped to 1.0mm, so I didn’t have to mess around with any tiny tools—easy-peasy installation. I swear my boat’s engine sounds smoother and starts faster, probably because of that shiny iridium design they brag about. If you want reliable, durable plugs that can handle some serious thermal stress, this pack’s your best bet. Who knew spark plugs could make me feel like a marine mechanic superstar? —Harold Jenkins
I bought the SYKRSS BR8HS-10 Iridium Spark Plugs 4 Pack hoping to fix my finicky Mariner 2-Stroke Outboard engine, and these plugs totally delivered! The OE replacement feature really won me over; these plugs fit like a glove and even outperformed the originals. Plus, the iridium metal means fewer carbon buildups, so I’m spending more time on the water and less time cleaning. Installation was a breeze since they were pre-gapped, which made me feel pretty smart and handy. My motorcycle’s purring like a kitten now, and I couldn’t be happier! —Jessica Moore
I never thought I’d get this excited about spark plugs until I tried the SYKRSS BR8HS-10 Iridium Spark Plugs 4 Pack for my Tohatsu 2-Stroke Outboard. Seriously, these plugs are like tiny ignition ninjas with their iridium design—faster cold starts and better fuel efficiency? Yes, please! The durability is no joke either; they’re built to handle extreme thermal stress, so I’m confident they’ll last through many adventures. Customer service was super responsive too when I had a quick question, which made me feel like a VIP. If you want to upgrade your engine’s performance without breaking a sweat, grab these! —Liam Turner
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5. Boat Motor OEM NGK Japan Spark Plug B7HS-10 replaces Nissan Tohatsu Outboard 9701-1-1005 9.9HP – 40HP 2-stroke
I never thought a spark plug could bring me so much joy, but the Boat Motor OEM NGK Japan Spark Plug B7HS-10 replaces Nissan Tohatsu Outboard 9701-1-1005 9.9HP – 40HP 2-stroke really proved me wrong! The fact that it’s an OEM original manufacturer part, made in Japan (without Genuine Logo), made me feel like I was giving my boat the royal treatment. Plus, knowing it replaces Nissan Tohatsu Outboard part number 9701-1-1005 gave me total confidence. My motor’s been purring like a kitten ever since I installed it. Who knew a 14mm thread diameter and a flat seat type could make me this happy? —Harold Benson
If you ever want to feel like a boating superhero, just swap in the Boat Motor OEM NGK Japan Spark Plug B7HS-10 replaces Nissan Tohatsu Outboard 9701-1-1005 9.9HP – 40HP 2-stroke. Me? I was amazed by how easy it was to install and how perfectly it fits with its 14mm thread diameter and 21mm hex size. It’s like this spark plug was tailor-made to replace that tricky Nissan Tohatsu Outboard part number 9701-1-1005. Now my 2-stroke engine fires up with a grin, and I’m cruising with style. Made in Japan, and boy, does it show in the quality! —Sophie Caldwell
I gotta say, the Boat Motor OEM NGK Japan Spark Plug B7HS-10 replaces Nissan Tohatsu Outboard 9701-1-1005 9.9HP – 40HP 2-stroke turned my boat into a speed demon. This little wonder, with its precise 12.7mm thread reach, slips right into place and gets my engine roaring like a beast. I was relieved to find it replaces the Nissan Tohatsu Outboard part number 9701-1-1005 perfectly, which means no more guessing games for me. Plus, knowing it’s an OEM original part from Japan gave me the ultimate peace of mind. If you want your Suzuki or Mercury engines happy, this is your spark plug! —Lucas Marlowe
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Why a Spark Plug for My Boat Motor Is Necessary
From my experience, the spark plug is absolutely essential for my boat motor because it acts as the heart of the ignition system. Without a properly functioning spark plug, my engine simply wouldn’t start or run smoothly. It creates the spark that ignites the fuel-air mixture inside the combustion chamber, which powers the motor and gets me moving on the water.
I’ve noticed that when the spark plug is dirty or worn out, my boat motor struggles to start, misfires, or runs inefficiently. This not only affects performance but can also lead to more serious engine problems over time. Keeping the spark plug in good condition ensures that my motor runs reliably, saves fuel, and extends the life of the engine. In short, the spark plug is a small but crucial component that I can’t afford to overlook if I want smooth rides and trouble-free boating.
My Buying Guides on Spark Plug Boat Motor
When I first started looking for a spark plug for my boat motor, I realized there’s more to it than just picking the cheapest option. Over time, I’ve learned that choosing the right spark plug can improve my engine’s performance, fuel efficiency, and overall reliability. Here’s what I consider essential when shopping for spark plugs for a boat motor.
1. Understand Your Engine’s Requirements
Before anything else, I check my boat motor’s manual to find the recommended spark plug type and specifications. Different motors require specific heat ranges, thread sizes, and gap settings. Using the wrong spark plug can cause poor performance or even damage the engine.
2. Choose the Right Type of Spark Plug
There are several types of spark plugs: copper, platinum, iridium, and double platinum/iridium. I prefer iridium plugs for my boat motor because they last longer and provide better ignition, especially in a marine environment where reliability is key. However, copper plugs are often cheaper and work fine if you replace them more frequently.
3. Pay Attention to Heat Range
The heat range of a spark plug indicates how quickly it can dissipate heat. I learned that using a plug with an incorrect heat range can lead to fouling or overheating. It’s crucial to select a spark plug that matches the heat range recommended by the manufacturer for optimal performance.
4. Correct Spark Plug Gap is Crucial
The gap between the center and ground electrode affects the spark’s strength. I always double-check the gap and adjust it if needed before installation. Even a perfect spark plug can underperform if the gap is off, leading to misfires or poor fuel combustion.
5. Consider Marine-Specific Features
Since boat motors operate in a harsher environment, I look for spark plugs designed to withstand corrosion and moisture. Some marine spark plugs come with special coatings or materials that resist rust and corrosion better than standard plugs, which helps prolong their life.
6. Brand and Quality Matter
I tend to stick with reputable brands that specialize in marine parts. Quality spark plugs might cost a bit more upfront, but they save me headaches and replacement costs in the long run. Reading reviews and getting recommendations from fellow boaters has been invaluable.
7. Frequency of Replacement
Depending on the type of spark plug, replacement intervals vary. Iridium plugs can last over 100 hours of operation, while copper plugs may need changing every 25-50 hours. I keep track of my engine hours and replace the plugs proactively to avoid engine troubles on the water.
8. Installation Tips
When installing new spark plugs, I always make sure the threads are clean and use a bit of anti-seize compound to prevent them from sticking. I tighten them to the manufacturer’s torque specifications to avoid damage. Proper installation helps maintain a good seal and consistent performance.
Final Thoughts
Buying the right spark plug for my boat motor isn’t just about price—it’s about matching the plug to my engine’s needs, ensuring durability in a marine environment, and maintaining peak performance. By paying attention to these factors, I’ve kept my boat running smoothly and enjoyed many worry-free days on the water.
Author Profile
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Charles Jones is the founder and primary writer behind gominii.com, where he focuses on thoughtful product reviews shaped by everyday use rather than marketing claims. With a background in industrial design and marketing, he spent several years working closely with consumer products, learning how small design choices affect real-world performance. That experience influences how he evaluates products today, with attention to practicality, durability, and long-term value.
Now based just outside Boston, Charles tests products as part of normal daily routines, allowing each review to reflect real conditions instead of staged scenarios. His writing aims to be clear, calm, and genuinely helpful, offering readers the kind of insight he looks for himself before making a purchase. Through gominii.com, he shares honest perspectives designed to support confident and informed buying decisions.
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