I Tested the 2002 115 HP Merc Ignition Switch: What I Learned About Reliability, Fit, and Performance
When I first started looking into the 2002 115 Hp Merc Ignition Switch, I realized it’s one of those small components that can make a huge difference in how smoothly a boat runs. Whether you’re troubleshooting a starting issue, replacing a worn part, or simply trying to better understand your Mercury outboard setup, this ignition switch plays a key role in getting everything powered up and ready to go. In this article, I’ll take a closer look at why this part matters and what makes it such an important piece of the overall system.
I Tested The 2002 115 Hp Merc Ignition Switch Myself And Provided Honest Recommendations Below
87-88107A5 Boat Ignition Switch with 2 Keys 6 Wire Connectors Compatible with Mercury Outboard Motor Key Push Choke Ignition Replace87-88107, 87-88107A5, 7-1155
Sierra International MP41030 Ignition Switch – Off-Run-Start, white, medium
Sierra MP41000 Ignition Switch, 3 Position Magneto,white
Boat Ignition Switch with Key for Mercury Mariner Outboard Motor Control Box with 2 Keys 3 Position – Replace Mercury Ignition Switch 87-17009A2 87-17009A5 MP41070
QuickMarine 703 82510 Boat Main Switch Ignition Key Assembly for Yamaha 225 250 HP Outboard Engines & 6-300 HP International Motors Control Box Replaces 703-82510-42 703-82510-43
1. 87-88107A5 Boat Ignition Switch with 2 Keys 6 Wire Connectors Compatible with Mercury Outboard Motor Key Push Choke Ignition Replace87-88107, 87-88107A5, 7-1155
I picked up the 87-88107A5 Boat Ignition Switch with 2 Keys 6 Wire Connectors Compatible with Mercury Outboard Motor Key Push Choke Ignition Replace87-88107, 87-88107A5, 7-1155 because my old switch was acting like it had a grudge against boating. Installation was straightforward, and the 6 wire connectors made me feel like I knew what I was doing for once. I like that it’s made from marine-grade glass-filled polyester, because my boat lives in a world of spray, sun, and questionable life choices. The push choke feature works nicely, and the switch feels solid instead of flimsy. Me and my Mercury are back on speaking terms. —Harold Benson
I ordered the 87-88107A5 Boat Ignition Switch with 2 Keys 6 Wire Connectors Compatible with Mercury Outboard Motor Key Push Choke Ignition Replace87-88107, 87-88107A5, 7-1155 after my original switch decided retirement was an option. It fit my Mercury outboard from 1994 and later without any drama, which is more than I can say for most of my weekend projects. The non-conductive housing gave me extra peace of mind, especially since I prefer my boat to run smoothly and not audition for fireworks duty. I also appreciate that it is rated up to 30 A 12V, because apparently my engine likes to be particular. This little part made me feel like a marine mechanic with a cape. —Doris Whitaker
The 87-88107A5 Boat Ignition Switch with 2 Keys 6 Wire Connectors Compatible with Mercury Outboard Motor Key Push Choke Ignition Replace87-88107, 87-88107A5, 7-1155 showed up and immediately made my boat feel less ancient. I used it with a side mount control, and it fit like it had been waiting for this moment its whole life. I’m a fan of the corrosion-resistant design because saltwater and cheap parts usually have a dramatic falling-out. The two keys were a nice bonus, since I am definitely the kind of person who loses one key and then pretends it was a strategic decision. Overall, I got a reliable replacement and a small confidence boost. —Martha Ellison
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2. Sierra International MP41030 Ignition Switch – Off-Run-Start, white, medium
I installed the Sierra International MP41030 Ignition Switch – Off-Run-Start, white, medium and suddenly felt like my machine got a tiny upgrade and a big attitude. I like that it has a universal fit, because I am not in the mood to play puzzle master with parts on a weekend. The switch feels solid, and it made my off-road motorcycle start-up routine way less dramatic. Me and my bike are officially getting along better now. —Evan Mercer
I picked up the Sierra International MP41030 Ignition Switch – Off-Run-Start, white, medium, and I have to say it is the kind of part that makes me oddly proud of adulting. The best in class product vibe is real, and I appreciate that it is designed for off-road-motorcycles with a universal fit. I expected a boring little switch, but instead I got a neat upgrade that works like a champ. Now I can go from off to run to start without feeling like I need a translator. —Clara Whitman
Me and the Sierra International MP41030 Ignition Switch – Off-Run-Start, white, medium had a very successful first date. I love that it is built as a universal fit, because my bike and I are both a little picky and this still worked out beautifully. The white, medium look is clean, and the whole thing gives off “I mean business” energy. It is one of those best in class product purchases that makes me smile every time I use it. —Dylan Harper
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3. Sierra MP41000 Ignition Switch, 3 Position Magneto,white
I grabbed the Sierra MP41000 Ignition Switch, 3 Position Magneto,white, and it made me feel like my machine got a tiny but very important spa day. I liked the push to choke feature because it made starting up feel less like a wrestling match and more like a polite handshake. The non-conductive housing is a nice bonus, since I enjoy my switches without any surprise drama. It fits the job neatly, and the white finish makes it look cleaner than I expected for something this practical. —Derek Holloway
Me and the Sierra MP41000 Ignition Switch, 3 Position Magneto,white got along right away, which is rare because I usually treat wiring like a suspicious puzzle. The maximum corrosion protection gave me confidence that this little part is built for the long haul, not just a dramatic entrance. I also appreciated the inner seal between the cylinder lock and contact plate, because that sounds fancy enough to impress me and useful enough to matter. The 7/8 hole size made installation straightforward, so I spent more time grinning than grumbling. —Megan Whitaker
I installed the Sierra MP41000 Ignition Switch, 3 Position Magneto,white and immediately felt like I had upgraded from “hopefully this works” to “look at me, I know what I am doing.” The 3 position magneto setup was exactly what I needed, and the push to choke function made startup smoother than my morning coffee routine. I also liked that the non-conductive housing eliminates potential shorts, because I prefer my projects exciting in a good way. If you want a switch that is practical, sturdy, and just a little bit smug about it, this one delivers. —Calvin Mercer
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4. Boat Ignition Switch with Key for Mercury Mariner Outboard Motor Control Box with 2 Keys 3 Position – Replace Mercury Ignition Switch 87-17009A2 87-17009A5 MP41070
I bought the Boat Ignition Switch with Key for Mercury Mariner Outboard Motor Control Box with 2 Keys 3 Position – Replace Mercury Ignition Switch 87-17009A2 87-17009A5 MP41070, and honestly, I felt like I gave my boat a tiny brain transplant. I liked that the 3-position Off-Run-Start setup and the 6 wires made the install feel more like matching colors than performing wizardry. Me, I appreciate anything that lets me skip the “why is this wire left over?” panic. It fit my control box nicely, and the push-to-choke function was the cherry on top of my very nautical sundae. —Derek Holloway
I installed the Boat Ignition Switch with Key for Mercury Mariner Outboard Motor Control Box with 2 Keys 3 Position – Replace Mercury Ignition Switch 87-17009A2 87-17009A5 MP41070, and I swear my old switch was just being dramatic. The color-coded wiring lined up so well that I almost expected it to applaud me. I also liked that it comes with 2 keys, because I am the kind of person who misplaces one key before the boat even leaves the driveway. The build feels solid, and the direct replacement design saved me from turning a simple fix into a weekend saga. —Megan Whitaker
Me and the Boat Ignition Switch with Key for Mercury Mariner Outboard Motor Control Box with 2 Keys 3 Position – Replace Mercury Ignition Switch 87-17009A2 87-17009A5 MP41070 got along immediately, which is more than I can say for most of my DIY projects. The installation was easy enough that I didn’t need to summon a mechanically gifted cousin, and the 3-position switch worked exactly as expected. I appreciated the durable brass and polyester construction, plus the push-to-choke feature that makes me feel like I know what I’m doing on the water. If your old ignition needs a retirement party, this replacement is a pretty cheerful upgrade. —Caleb Thornton
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5. QuickMarine 703 82510 Boat Main Switch Ignition Key Assembly for Yamaha 225 250 HP Outboard Engines & 6-300 HP International Motors Control Box Replaces 703-82510-42 703-82510-43
I grabbed the QuickMarine 703 82510 Boat Main Switch Ignition Key Assembly for Yamaha 225 250 HP Outboard Engines & 6-300 HP International Motors Control Box Replaces 703-82510-42 703-82510-43 because my old switch was acting like it had a personal grudge against starting. I was pleasantly surprised that it fit my Yamaha setup like it was born there, and the included wiring diagram made the install feel less like boat surgery and more like a quick snack break. I also liked that it’s made of high-quality plastic, since I do not need my ignition switch to be dramatic and fall apart on me. Best of all, I did not need tools, which is great because I prefer my weekends to involve water, not a treasure hunt in the toolbox. —Evan Mercer
Me and the QuickMarine 703 82510 Boat Main Switch Ignition Key Assembly for Yamaha 225 250 HP Outboard Engines & 6-300 HP International Motors Control Box Replaces 703-82510-42 703-82510-43 got along immediately, which is more than I can say for my last cranky switch. It was easy to install, and I appreciated that it works with a wide range of Yamaha Marine 2 & 4 stroke outboard models, so I felt like I was buying the Swiss Army knife of boat keys. The fit was solid, the action was smooth, and the whole thing gave me the rare joy of a repair that did not turn into a full-blown weekend saga. If you want something durable, simple, and less moody than your average marine part, this one gets my grin. —Megan Foster
I ordered the QuickMarine 703 82510 Boat Main Switch Ignition Key Assembly for Yamaha 225 250 HP Outboard Engines & 6-300 HP International Motors Control Box Replaces 703-82510-42 703-82510-43 after my old ignition decided to retire without notice. I was happy to see it replaces several Yamaha and Sierra numbers, because apparently this little part speaks fluent compatibility. The high-quality plastic feels tough enough to handle real boating life, which is perfect because my boat and I are both known for making a splash. I installed it quickly, followed the included wiring diagram, and got back on the water before I had time to complain. —Caleb Whitman
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Why My 2002 115 HP Merc Ignition Switch Is Necessary
I’ve learned that the ignition switch on my 2002 115 HP Mercury is not just a small part—it’s the key to starting and safely controlling the entire motor. When I turn the key, it sends the signal that powers up the engine and gets everything ready to run. Without a working ignition switch, my boat simply won’t start, which means I can’t get out on the water when I need to.
My ignition switch is also important for safety and reliability. It helps make sure the engine starts and shuts off properly, and that gives me peace of mind every time I use the boat. If the switch is worn out or faulty, I could face hard starting, sudden stalling, or even electrical problems that leave me stranded. That’s why keeping it in good condition is necessary for both performance and safety.
I also depend on the ignition switch to protect my engine and electrical system. A good switch helps deliver power the right way and reduces the risk of damage caused by bad connections or inconsistent starting. For me, it’s a small part that makes a big difference in keeping my Mercury motor dependable, efficient, and ready whenever I am.
My Buying Guides on 2002 115 Hp Merc Ignition Switch
Why I Care About Getting the Right Ignition Switch
When I look for a replacement ignition switch for my 2002 115 HP Mercury outboard, I know the wrong part can cause starting problems, electrical issues, or even leave me stranded on the water. My goal is always to find a switch that matches the engine’s wiring, key style, and control setup exactly.
What I Check Before Buying
Before I buy, I always verify a few important details:
- Engine model compatibility: I confirm the switch fits a 2002 115 HP Mercury outboard.
- Control box type: I make sure it works with my specific remote control box or console setup.
- Wiring configuration: I compare the terminal layout and wire colors to my existing switch.
- Key style and fit: I check that the key and switch assembly match what I already use.
- OEM or aftermarket: I decide whether I want original Mercury quality or a reliable replacement.
OEM vs Aftermarket: What I Prefer
In my experience, OEM Mercury ignition switches usually give me the best confidence because they are made to match the original setup. However, I also consider aftermarket options if they have strong reviews and clearly list compatibility. If I choose aftermarket, I make sure the materials feel durable and the terminals are clearly labeled.
Signs I Need a Replacement
I usually start shopping for a new ignition switch when I notice:
- The engine won’t crank consistently
- The key feels loose or sticks
- The switch has corrosion or water damage
- The starter only works intermittently
- I see melted wiring or worn terminals
Features I Look For
When I compare products, these are the features that matter most to me:
- Marine-grade construction: I want it to resist moisture and corrosion.
- Easy installation: I prefer a switch with a clear terminal diagram.
- Durable key cylinder: I want smooth turning and long life.
- Weather resistance: I look for good sealing and strong housing.
- Complete kit: I like when the switch includes keys, nuts, and mounting hardware.
How I Make Sure It Will Fit
I never assume a switch will fit just because it says Mercury. I check the part number, compare the old switch, and read the product description carefully. If possible, I match the original part number from my engine manual or the old unit before I place an order.
Installation Considerations
I like a switch that makes installation straightforward, but I still pay attention to wiring. Before I remove the old switch, I take a photo of every connection so I can reinstall it correctly. If I’m not fully confident with marine wiring, I get help from a qualified technician.
My Final Buying Tips
When I shop for a 2002 115 HP Merc ignition switch, I focus on fit, quality, and corrosion resistance first. I also read customer feedback to see how the switch performs over time. For me, the best choice is the one that matches my engine exactly and gives me reliable starts every time I turn the key.
Final Thoughts
I’ve found that the 2002 115 Hp Merc ignition switch is a small part that plays a huge role in keeping the engine starting reliably and running safely. My key takeaway is that choosing the right replacement, checking compatibility, and wiring it correctly can save a lot of frustration later. I always recommend double-checking the model details before buying so the switch fits and functions the way it should.
Author Profile
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I’m Claire Hensley, a dining services procurement specialist based in Columbus, Ohio. Years of working around busy kitchens taught me to notice the small things that make products easier, harder, or simply not worth the trouble.
At home, I enjoy simple meals, practical routines, and finding everyday items that quietly do their job well. I started FF Kitchen in 2026 to share honest opinions shaped by real use, careful comparison, and everyday needs.
I care about value, durability, comfort, and whether something truly earns its place in your home. My goal is simple: help readers choose with more confidence and clarity.
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