My Chainsaw Won’t Idle – Here’s Why (3 Common Reasons)

| Last Updated: February 6, 2021

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There are many possibilities as to why your chainsaw won't idle, the most common being a clogged air filter.

However, it could also be a fault with the idle function like clogging or a broken part.

In the article below, we'll understand these issues and provide you with the best solutions. 

Why Your Chainsaw Won't Idle

Here are the three most common reasons why your chainsaw won't idle:  

  1. Your air filter needs to be cleaned 
  2. It's time to clean your carburetor 
  3. You need to adjust the carburetor

Clean The Air Filter

This solution is pretty simple and often overlooked. Due to the number of dust particles and dirt created by a chainsaw, it can become matted in dirt, which can affect other components like the Carburetor. 

You can clean the air filter by taking it out and removing any visible debris; giving it a clean with a brush can remove those smaller particles stuck between the small holes. If there's any damage to the filter, it has to be replaced. 

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Adjust The Carburetor

Adjusting the Carburetor is quickly done by turning either the L or H screws located at either side of your chainsaw. Ensure that you remember how many quarter turns you make just in case you have to restart. 

We adjust these screws to increase or decrease the amount of fuel provided, which in turn affects the chainsaw's ability to idle correctly. You simply adjust the L screw a quarter turn, counter-clockwise. 

If it needs even more fuel, you can turn the L screw another quarter in the same direction. You'll need to play around with it and test the chainsaw to get it to an appropriate point that it can idle properly. 

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Clean The Carburetor 

Like the air filter, your Carburetor can also become clogged with particles, affecting the chainsaw's idling.

You'll need to open up the chainsaw and unscrew the Carburetor to get a better look. This is relatively easy to do; on most chainsaws, it's located directly behind the air filter. 

Remove the Carburetor's top plate, which protects the pumping diaphragm; if there's any dirt or grime, give it a clean with pressurized air and a brush. Take the diaphragm off and inspect what's underneath and clean if necessary. 

Once the top plate has been reattached, you can inspect the bottom plate; there can be the same issues of dirt and particles. 

However, a common issue is a warped mitering diaphragm, which could be the reason for our idling problems. This looks like wrinkles on the rubber covering; this can easily be replaced. 


Chainsaw idling is a common issue that usually is caused by the same reasons mentioned above. If you follow our solutions, the chances are you're going to solve the idling problem. They don't take that long to complete if you do it properly.

If you'd like a visual guide on how to complete these solutions, please take a look at the video below.