Updated February 12, 2024

How To Change Your Generator Spark Plug – 7 Steps Replacement

Replacing the spark plug in your open-frame generator is a straightforward and important maintenance task to ensure your generator runs smoothly and efficiently.

A well-maintained spark plug is responsible for the ignition process in your generator engine. In this seven-step guide, we’ll walk you through the process of how to change generator spark plug and provide a video guide for specific models and brands to help you maintain its reliability and performance.

It’s important to follow these instructions carefully and refer to your generator owner’s manual for specific details, as procedures may vary by make and model.

How To Change Generator Spark Plug

When to Change a Spark Plug?

It’s generally recommended to change the spark plug in a generator after every 100 to 150 hours of use or at least once a year, whichever comes first. But it’s my recommendation that 200 to 300 hours of use are normal, otherwise, if there are no symptoms of a faulty plug,

However, if you notice any signs of wear if your generator is not running smoothly, or if it drinks more fuel, it’s a good idea to check and possibly replace the spark plug sooner.

It’s also smart to check the spark plug now and then for any signs it’s worn out, like if the part that sparks is dirty or broken. If you see that, put in a new one.

What Does Spark Plug Do?

A generator spark plug plays a crucial role in the ignition process of the engine. When the generator is started, the spark plug generates a spark that ignites the air-fuel mixture within the engine’s combustion chamber.

This spark is what starts the engine running, making the generator produce power. The spark plug is what gets the engine going smoothly. If the spark plug doesn’t work well, the engine might not start or run properly.

The engine may struggle to start or run inefficiently, leading to reduced performance. That’s why it’s important to keep an eye on it and replace it when needed.

So, How To Change Generator Spark Plug?

Find the spark plug location and discontent the plug cap boot, then remove the old plug using the socket, examine the old plug, and install the new spark plug with the correct recommended gap using a gaping tool. Last, reattached the earlier removed plug cap wire boot to the spark plug.

Tools and Materials 

  • Clean brush & WD40
  • New spark plug with the correct gap
  • Spark plug gaping tool
  • Ratchet or Spark plug socket wrench
  • Spark plug socket 3/8 or 5/8

Before you begin any maintenance tasks on your generator, make sure to follow the correct safety measures. This includes turning off the generator, taking off any power connections, and letting it cool down before you access the spark plug.

Step 1: Locket the Spark Plug

Some people ask where the spark plug is located. The spark plug is a small but vital part of your generator’s engine. It’s typically located open-frame on the cylinder head of the engine block, and it is commonly hidden below a removable casing and protected by a spark plug boot.

Sometimes, the spark plug might be in a hard-to-reach spot. You might need to take off other parts or take apart the engine to get to it. But in newer inverter generators, it’s behind a side plate.

If you are having trouble finding your spark plug location, check out the user manual. It might reveal where it might be hidden and how to gain maximum access to it. Moreover, some brands and stronger models may come with multiple spark plugs.

Step 2: Disconnect Spark Plug Boot

Once you have found where your old spark plug boot is installed, disconnect the spark plug boot from the spark plug itself. To do this, grip the spark plug boot (the thick part of the wire) and pull it straight off the spark plug. Avoid pulling on the wire itself to prevent damage.

Step 3: Remove Old Spark Plug

After removing the spark plug boot from the plug, using a spark plug socket wrench, begin to loosen the old spark plug by turning it anticlockwise. If you need a spark plug socket 3/8 or 5/8, use it.

If your generator’s spark plug is located deep within the engine, you might need a socket wrench extension to access it effectively. Continue turning until the spark plug can be removed by hand.

Step 4: Inspect Old Spark Plug

Take a moment to closely check the old spark plug. Clean the aging plug and its housing around it, and confirm the removal of any black residue and debris from the plug. For this job, utilize WD40 and a clean brush.

Follow these instructions to determine the old spark plug’s condition:

  1. Connect the plug cap to the old plug and hold it close to the crankcase; don’t screw it in a hole. Note that you are holding the plug cap in your hand, not a plug.
  2. Attempt to manually start the generator using the recoil starter, giving it multiple tries.
  3. If you observe a robust blue spark, it indicates that the spark plug is in good working condition.
  4. If the sparks appear weaker or have a full yellow spark, it’s time to replace the plug.

If no sparks are seen, there may be an issue with the ignition coil. It’s time to change the ignition coil, otherwise, continue the next step.

Step 5: Gap Adjustment New Spark Plug

The plug gap is important Check your generator’s owner’s manual or the manufacturer’s specifications for the recommended spark plug gap size.

This gap is the distance between the center electrode and the ground electrode and is crucial for proper ignition.

If you are still not sure if you have the correct gap, use a spark plug gapping tool to adjust the gap on the new spark plug to the required size, if necessary.

Step 6: Install the New Spark Plug

Thread the new spark plug into the spark plug hole by hand. Start by turning it clockwise to ensure it goes in smoothly. Do not cross-thread it; it should thread easily.

Once it’s threaded in by hand, use your socket wrench or spark plug socket and ratchet to tighten it snugly. Usually, a quarter-turn to an eighth to six turns after it touches the cylinder head is sufficient. Be cautious not to overtighten, as this can damage the spark plug or cylinder head.

Step 7: Reattach the Spark Plug Boot

With the new spark plug securely in place, it’s time to reconnect the generator spark plug wire. Push the plug cap rubber boot of the wire firmly onto the spark plug until you feel or hear it click into the right position.

Verify that it is securely attached to the spark plug to prevent any electrical arcing or disconnection during engine operation.

Make sure all connections are safe by taking a moment. Check to make sure there are no loose wires or components near the spark plug area.

Video Guide to Replace Generator Spark Plug?

This is important to verify Since we are aware that every generator brand and model is different, it’s challenging to give you a single, detailed guideline.

For this purpose, we are providing you with an entire section of video instructions on how to change spark plugs in generators of multiple brands and types.



Champion 3100 Watt 

3500 Watt 

2000 Watt

Honda  EU7000is 



Generac  IX2000 




Cat INV2000 


Ryobi  RYI2200
Westinghouse  7000 Watt
Predator  3500 Watt
Firman  W3650IR
Briggs and Stratton 8000 Watt

If your specific brand or model is not listed on the list, please contact us and mention your particular brand and model. We will try to mention your desired video for your brand in this article as soon as possible.


Luckily, we covered every step of the replacement process for a traditional generator spark plug. When these steps are carefully taken, the highest performance and dependability are guaranteed. Both the longevity of your generator and its use in emergencies and other scenarios are extended.

Please maintain a detailed record of all maintenance procedures, like filter cleaning and oil change, and consult your generator’s owner manual for specific recommendations for each model. When your generator is properly maintained, it can run when you require backup power.


Why is changing the spark plug important for my generator?

It is essential to change the spark plug because it provides optimal engine ignition and consumption. Starting issues, reduced energy efficiency, and poor generator performance might be caused by a damaged or fouled spark plug.

How often should I change the spark plug in my generator?

Depending on the generator’s make and model, use, and spark plug type, different spark plugs require different amounts of replacement. As a general rule, it is advised to check the spark plug and maybe replace it once a year or after 100 hours of operation.

How do I determine the correct spark plug for my generator?

To find the right spark plug for your generator, check your generator owner’s manual. It will provide the specific spark plug type and gap recommended by the manufacturer. Using the wrong spark plug can lead to performance issues.

Can I clean and reuse a spark plug instead of replacing it?

While it’s possible to clean a fouled spark plug, it’s not recommended for long-term reliability. Cleaning may temporarily improve performance, but replacing it with a new spark plug is the best practice for maintaining optimal generator operation.

What are the signs that my generator’s spark plug needs replacement?

Common signs that your generator spark plug may need a replacement include difficulty starting, misfires, increased fuel consumption, and a visible build-up of carbon or deposits on the spark plug’s electrodes.

About Saad Ahmed
Hi am Saad Ahmed and as you can see that i have been a generator mechanic for the past 12 years of experience in this industry. But now i am Full time digital marketer and affiliate blogger.