How to Change Spark Plugs on Onan 5500 Generator- Easy Steps

Do you have any generators? If so, then you have to know about some essential parts. Without that, your generator will not perform well.

Nowadays, a generator is essential for many purposes. Onan 5500 generator is at the top of the list of selling. To keep the generator active and well, you have to know about its parts. The most important part is the spark plug, which is small in appearance but helps start the generator.

It is time to replace the spark plug if you get weak or low performance from your generator. It’s not that tough work if you have an idea about it. Here, we will tell you how to change spark plugs on Onan 5500 generator

How to Change Spark Plugs on Onan 5500 Generator

It is crucial to change the spark plug on time. If you don’t maintain this, there could become an accident.

Before changing the plug, you must make sure that the power of the generator is off. After that, unplug all cords. If you turn on the machine before changing the plug, make sure that it is not overheated. That’s why you should wear glasses and gloves.

After finishing all this work, you can take these steps.

Step 1: Find The Spark Plug

Locate the spark plug is the first step. If you are doing it for the first time, then it might be difficult for you. It is kept under a removable casing and covered with a spark plug boot.

The easiest way to detect your spark plug is to look for a black wire attached to the engine, follow it, and look at the boot’s end.

Still, if you don’t find the spark plug, then you can read the onan 5500 generator operator manual. It will help you to locate the spark plug.

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Step 2: Separate Plug Cable

Once the location of the plug is found, it needs to be disconnected from the cable boot. To do this safely, you need to get access to a spark plug cable boot.

Once you have proper access, grab the boot, twist it in both directions, and pull it. This way, you can loosen the wire a bit more easily. For this, you can remove the plug cable.

Never pull the cable part because you can easily damage it.

Step 3: Clean The Parts

After disconnecting the cable, you need to clean everything around in the generator. It is an important step. If you are careless about the cleaning process, then it could be bad for your generator.
So make sure you clean up any oil, dirt, and residue.

Step 4: Put Apart The Old Plug

The old plug needs to be removed after cleaning everything. You will need a socket and a ratchet to remove the spark plug. Once you get the right socket, you need to connect it to the spark plug manually.

Our suggestion is to use the ratchet to loosen the spark plug and remove it.

Step 5: Check The New Plug

Make sure you have the right size & model before putting the new spark plug in the generator. It would help if you used a gap measuring tool for checking the onan 5500 spark plug gap. Also, it is very reasonable.

If everything goes well after the new plug measurement, you can go to the next step.

Step 6: Installation

The installation of the new spark plug in the generator is the most crucial step. If the installation goes wrong, then your engine could be damaged.

Grab the empty spark plug socket, put the new plug into it, and place it in your engine’s empty place. You can shake it a bit with it until it sits properly and starts rotating it very gently.

Then, tighten the spark plug by attaching a ratchet to the socket. You can remove the ratchet and the spark plug socket after tightening the new plug.

Step 7: Reconnect The Plug Cable.

Once the new spark plug is in place, you will need to reconnect the cable. Again, take the boot of the spark plug cable and slide it then, press it until it is fully inserted.

You will hear a click after the plug enters the correct position from the connector. You can reattach the cover you had to unload after the plug reconnected. After completing all the steps, you should check the generator to see if everything is ok.

After this, you know how to change spark plugs on Onan 5500 generator very well.

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Onan 5500 Generator Maintenance

The maintenance of the generator is necessary. We recommend some general maintenance to keep your machine active and for longevity. Here are some tips for you.

  • Check your battery and connection monthly. You have to clean your generator regularly.
  • Keep watching the performance of your generator.
  • You should change the oil and oil filter every 150 hours and replace the spark plug every 450 hours.
  • Do not turn on the generator for a long time.
  • Always use clean oil in your generator. It gives you impressive performance.
  • Keep the user manual guide in a safe place. When you need any information, it will help you.


Many people nowadays use Onan 5500 generators. Not many people know about its parts. So if the generator doesn’t work correctly, they call a mechanic and spend a lot of money.

That’s why Onan users need to know about their generator’s part. The spark plug is mainly used to boost the generator’s power. For this, your generator runs like a horse.

If you don’t change the spark plug on time, there could be an accident. So, you should put the plug on time. You will get superb performance. After that, you will repurchase this generator.

So, this is the way how to change spark plugs on Onan 5500 generator