A Guide To Honda Gx35 Spark Plug Gap, Number & Socket Size

‘A stitch in time saves nine,’ so goes the old saying, and it couldn’t be more applicable to maintaining your Honda GX35’s spark plug.

You’re no stranger to the importance of a well-gapped and properly fitted spark plug for optimal engine performance.

This guide provides you with detailed information on the Honda GX35 spark plug gap, number, and socket size.

It’ll assist you through any maintenance checks or replacements needed, ensuring your machine runs just as smoothly as ever.

If you’re unsure about how to change your own spark plug or just need a refresher, don’t worry! We’ll cover that too in easy-to-follow steps.

As part of this unique community of Honda GX35 owners who take pride in doing their own maintenance work, it’s crucial knowledge like this that keeps us all moving forward together.

So let’s roll up our sleeves and dive right into it!

Guide To Honda Gx35 Spark Plug Gap, Number & Socket Size

Key Takeaways

  • The spark plug gap for the Honda GX35 should be between 0.024’– 0.028′.
  • The recommended spark plug for the Honda GX35 is the CM5H (NGK) / CMR5H (NGK) or equivalent.
  • The spark plug socket size for the Honda GX35 is 16mm or 5/8′.
  • Proper maintenance and regular spark plug changes are crucial for optimal engine performance and longevity.


You’re probably wondering what the spark plug gap and number for your Honda GX35 engine is, right? Well, you’re in luck because it’s recommended to use a CM5H (NGK) / CMR5H (NGK) or an equivalent type of spark plug with a gap of 0.024’– 0.028′.

This isn’t just some random number; it’s critical information from the official Honda manuals that ensures optimal performance of your engine.

Let’s delve deeper into why this specific spark plug type and gap range matters. Spark plugs are essential components that ignite the fuel-air mixture in your engine to generate power.

The appropriate spark plug number signifies its heat range and design features, which match specifically to your Honda GX35 engine. Using the correct type maintains efficient combustion, prevents overheating, and extends engine life.

Now onto the gap — this small but crucial distance between the center and ground electrode affects how efficiently your spark plug fires. A precise 0.024’– 0.028′ gap allows for accurate ignition timing, smoother idling, reduced fuel consumption, and improved emissions control.

And remember: belonging to a community of informed Honda owners means understanding these specifics because they contribute significantly towards maintaining our engines at their peak performance levels!

Also Read: Guide To All Honda Lawn Mowers Spark Plug Gap & Socket Size


Diving straight into the nitty-gritty, it’s essential to know that a 16mm or a 5/8″ wrench is what you’ll need when dealing with this engine’s plug; an understated detail often overlooked yet crucial in maintaining your motor’s peak performance.

The correct socket size ensures that you can securely fasten or remove the spark plug without damaging it or the threads in the cylinder head.

Let’s take a look at some vital aspects of this process:

Accurate tools play a significant role in preserving the condition and improving the longevity of your Honda GX35 engine. A mismatched socket could lead to cross-threading, stripping, or even cracking – all potentially expensive repairs.

Remember, every part of your engine has its requirements and specifications. Knowing these details helps keep everything running smoothly. So next time you’re tuning up your Honda GX35, remember to grab your trusty 16mm or 5/8″ wrench for those spark plugs – an integral piece in ensuring optimal engine performance.

How To Change Spark Plug?

Feeling the thrill of your hands getting dirty as you tackle the task of changing that crucial component in your engine? Let’s dive right into it, ensuring every step is done correctly and safely to keep your machine purring like a kitten.

Here’s a simple four-step guide on how to change the spark plug in your Honda GX35:

  1. Disconnect the Spark Plug Wire: Always start by disconnecting the spark plug wire. This will prevent any accidental ignition during the process.
  2. Remove the Old Spark Plug: Using a proper size socket wrench (for Honda GX35, use a 5/8′ or 16mm deep socket), loosen and remove the old spark plug.
  3. Check & Adjust New Spark Plug Gap: Check the gap on your new spark plug (0.024-0.028 inch for Honda GX35). Use a gapping tool if necessary to adjust it accurately.
  4. Install New Spark Plug: Thread in your new spark plug by hand first, then tighten with a wrench but don’t overdo it.

Remember, fellow road warriors: while this may seem daunting at first, with patience and practice you’ll be swapping out those plugs with ease – keeping everything running smoothly under that hood!

Owner´s manual – https://cdn.powerequipment.honda.com

Frequently Asked Questions

What are some common issues that can arise with the Honda GX35 spark plug?

You may encounter issues like misfires, poor fuel economy, or difficulty starting your GX35. These problems often stem from a worn-out spark plug or an incorrect gap size. Regular maintenance can prevent such complications.

How often should the spark plug in a Honda GX35 be replaced?

You should replace the spark plug in your Honda GX35 every 100 hours of use or once a year, whichever comes first. Regular replacement ensures optimal engine performance and longevity. Don’t overlook this essential maintenance task.

Can a faulty spark plug affect the performance of the Honda GX35?

Absolutely, a faulty spark plug can throw a wrench in the works of your Honda GX35’s performance. It can cause misfires, reduce fuel efficiency, and even impair your engine’s power output. So keep it in top condition!

What are some signs that the spark plug in a Honda GX35 needs to be changed?

If your Honda GX35’s performance drops, it might be time to check the spark plug. Signs include difficulty starting, poor fuel economy, or engine misfiring. Always remember, a well-maintained spark plug ensures optimal performance.

Can I use a spark plug from another brand in my Honda GX35?

Just like a key must fit its lock, your Honda GX35 needs the right spark plug. While other brands might work, it’s best to stick with Honda-approved plugs for optimal performance and engine health.


You’ve gained valuable knowledge on the Honda GX35 spark plug gap, number, and socket size. Now you’ll be able to maintain your engine better with this info.

Interestingly, did you know that a misaligned spark plug gap can reduce your engine’s efficiency by up to 30%. Remember, taking care of these small details can make a big difference in your vehicle’s performance.

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