What is The Correct Size for The Yamaha Outboard Spark Plug Socket?
Why is it important to get the ideal spark plug socket size? Well, if the socket is too big, the spark plug will fall right off and possibly break the insulator. On the other hand, if the socket is too small, the spark plug won’t get into the socket. Either way, there won’t be the spark needed to ignite the combustion of the engine. In other words, the engine won’t start. This is why it’s important to know what size the spark plug socket is.
If you are confused about the Yamaha outboard spark plug socket size, this is the article for you. Here you will get to know the ideal size of the spark plug for this particular engine and all the other information you need to know.
The Yamaha Outboard Spark Plug Socket Size

Ibanez in iFish.net commented,
“16mm, 18 mm, or 13/16 are the three sizes for Yamaha.”
The initial question was regarding the ideal socket size for a spark plug in a Yamaha outboard. Although many answers suggested otherwise, the most common ones approved of what Ibanez said. But what does his comment mean?
These numbers basically indicate the diameter of the socket. In other words, this size determines how long or short the girth of the spark plug can be. In the mentioned comment, 16mm and 18mm means the ideal width of the socket for the right spark plug is 16 mm or 18 mm long. Both sizes will go well with your Yamaha outboard.
Now, only the 13/16 bit is left. It’s actually 13/16” (inches). This fraction indicates a diameter in mm, just like before. The 13/16″ means 21 mm. You can check out this chart from tengtoollsusa.com to get a clearer idea of how the sizes are converted.
So, to wrap it up, the socket size (or length of the socket) of the Yamaha outboard spark plug can be 16 mm, 18 mm, or 21 mm (13/16”). These are the most likely options.
But this doesn’t quite clarify how you can know the size of your Yamaha outboard model. Check out the next point to know more about it.
How to Know the Right Yamaha Outboard Spark Plug Socket Size
It’s not difficult to find out the ideal spark plug socket size for your Yamaha outboard. Firstly, check the manual of your outboard. The information you are looking for should be there. However, if you fail to consult the manual, there is a certain strategy you can adapt to identify the number. Here’s what you can do,
- Take a caliper
- Place one end of the caliper on one side of the socket
- Pull the other pointer toward the opposite part of the socket hole
- Carefully note the measurement you get in the mm
This is the spark plug socket size you have been looking for. Now that you got the number, there shouldn’t be any further difficulty finding the right socket.
Frequently Asked Questions (FAQs)
There are 2 types of sparks plug sockets. Namely, magnetic and rubber grommet spark plug sockets.
No, regular sockets can’t be used for spark plugs as they miss the rubber feature. This may cause the spark plug to break in case of replacement.
No, there are no universal socket sizes.
Conclusion
Now that you have a clear idea of the Yamaha outboard spark plug socket size, nothing should go wrong in finding the ideal spark plug. The replacement process should go smoothly as well. The best thing is you have learned to measure the spark plug socket size all by yourself. Everything related to the spark plug socket should be completely clear to you now. So, follow this article’s lead and get your work done without any hassle.
You Can Also Read: