Chainsaw Won’t Stay Running [6 Easy Fixes]

Are you having trouble getting your chainsaw to stay running? You’re not alone. Many people have experienced this problem, and it can be both frustrating and time-consuming. But don’t worry—in this blog post, we’ll discuss all the potential issues causing a chainsaw to fail to start or run properly, as well as how you can go about fixing them!

So let’s get started on troubleshooting your saw so that you can get back to cutting wood with ease.

The Most Common Causes of Chainsaw Issues

Chainsaws are invaluable tools for both professional and amateur woodworkers alike, however, if your chainsaw won’t stay running, it can be a real pain. Here are 6 common reasons why a chainsaw won’t stay running and how to fix them:

1. Old Gas / Bad Fuel

2. Bad Spark Plug

3. Bad Carburetor

4. You Have a Flooded Engine

5. Improper Carburetor Adjustment

6. Compression – Air Problems

1. Old Gas/ Bad Fuel

Chainsaw Won't Stay Running

The performance and efficiency of a chainsaw’s engine depend a lot on the quality of the fuel. Low-octane fuel or fuel that has been sitting for a long period of time can cause the chainsaw to have issues when starting. Also, old fuel leaves gunk in the tank, clogging the fuel filter and carburetor. A clogged fuel filter can prevent the saw from starting.

What exactly is low-octane fuel? A low-octane fuel is one that has a lower octane rating than the recommended fuel for your saw. Also, it can be harmful to the engine if the saw is not used for 8 weeks or more.

Fuel with a rating of 89 octanes or lower is considered low-octane fuel. This type of fuel is generally not recommended for use in chainsaw engines because it causes engines to have a hard time running.

How To Fix

Solution: Make sure to always use fresh fuel in your chainsaw, as old fuel can cause starting issues and damage the engine. Also, make sure that you are using fuel of the correct octane rating for your saw.

2. Bad Spark Plug

Chainsaw Won't Stay Running

A spark plug is what starts the engine, and having a bad spark plug is also an issue that can cause your chainsaw to not start. If you’ve got a bad spark, you may notice that your saw will lose power and stop more frequently than usual. When you’re cutting wood, your saw will lose power, which is a sign that you should change or clean your spark plug.

How To Fix

If you notice any signs of damage to the spark plug, you should clean or replace the spark plug. Signs to look for include cracks on the porcelain insulator, carbon build-up at the electrode, and damage and excessive light in the electrode.

Cleaning or replacing your spark plug can help get your chainsaw running properly. Make sure to use a spark plug that is compatible with your saw and follow the manufacturer’s instructions when changing it.

3. Dirty or Clogged Carburetor

Chainsaw Won't Stay Running

A dirty or blocked carburetor can cause your saw to start and then quickly shut off.

The signs that your chainsaw carburetor needs to be cleaned are—the engine not starting, an excessive amount of air in the fuel, excess fuel in the air and fuel mixture, and a flooded engine.

If you’re facing any of the above issues, it is time to clean your dirty or blocked carburetor.

How To Fix

To fix a dirty or clogged carburetor, you’ll need to first use a diluted cleaner such as detergent or some other type of cleaner.

You should clean the clogged air filter of your saw before cleaning the carburetor. The air filter is responsible for filtering out any particles and impurities in the air that could damage the engine of your chainsaw. Make sure to clean the air filter thoroughly with the cleaner and then dry it.

Now, unlink the carburetor using pliers and a screwdriver. After removing the carburetor,  spray the cleaner inside it and shake it to make sure that all dirt and debris are washed away.

You can also, soak the carburetor in a large container with a mixture of cleaning detergent and water and let it float for some time. Use a brass brush to scrub away the dirt and debris from inside the carburetor.

Once you have cleaned the carburetor, reassemble it on the engine.

4. You Have a Flooded Engine

Chainsaw Won't Stay Running

Sometimes, due to incorrect starting techniques, the engine can become flooded with too much fuel. This happens when you pull the starter rope more than a few times without giving it enough time to start. A flooded engine releases a gasoline smell in the air when you pull the starter rope.

When a flooded engine releases a gasoline smell in the air, it is a sign that too much fuel has been released and the engine may not start.

How To Fix

To fix the flooded engine, pull the starter rope several times while throttling down. You should also wait a few minutes before starting the engine again, as this will allow the excess fuel to evaporate and help get the engine started.

You should also check the spark plug, as a poor spark can prevent your chainsaw from starting.

5. Improper Carburetor Adjustment

Sometimes, even after cleaning and replacing the spark plug, your saw may not start. This could be caused by a carburetor that needs to be adjusted. A carburetor regulates the air and fuel mixture that is needed to start the engine. Your carburetor screws (idle, high, and low) need to be adjusted so that the chainsaw will stay running and won’t stop.

An improperly adjusted carburetor can cause an engine to run poorly or not start at all.

How To Fix

Adjusting the carburetor can be hard for a beginner, and it often takes more than one change to get it right. To adjust the carburetor, you’ll need a flathead screwdriver and an adjustable wrench. You should turn each of the screws (idle, high, and low) clockwise until the engine is not having running issues. You can also use an engine speed measuring tool to adjust low, idle, and high speeds.

Once the adjustments are complete, the chainsaw should stay running

6. Compression – Air Problems

Chainsaw Won't Stay Running

It’s a signal that there’s internal damage like bad piston rings, bad crankshaft seals, or a cracked piston. Fixing these damages is expensive, and they are a signal that maybe it’s time to buy a new chainsaw. That’s why it’s better to do a compression test before spending money on relatively expensive parts like a new carburetor

If your chainsaw is not starting or staying running, then you may be facing compression issues. A lack of compression can cause internal damage to piston rings or cracked pistons. You can check the compression by using a compression gauge. Smaller saws should have more than 70 PSI, and bigger saws should have 100 PSI.

How to Fix

If the compression test results are lower than expected, then you will need to replace the piston rings, camshaft, head gasket, valves, or a cracked piston.


Chainsaw won’t stay running FAQs

Why does my chainsaw keep dying?

There are many reasons why your chainsaw might be dying or stopping when you give it gas. Possible causes are a dirty air filter, clogged fuel lines, a carburetor that isn’t set up right, broken spark plugs, or a problem inside the engine, like a cracked piston. If your chainsaw is having trouble staying

Why does my chainsaw stall out when idling?

Your chainsaw might stall out when idling if the carburetor is not adjusted properly. The carburetor may need to be adjusted so that the engine is getting enough air and fuel.

In conclusion, there are many potential reasons why your chainsaw won’t stay running. It could be due to air or fuel delivery problems, spark plug issues, a flooded engine, improper carburetor adjustments, or compression-air problems.

If you’ve done all the troubleshooting steps and still haven’t been able to get your chainsaw running properly, then it might be time for a new one.

We hope that this article has helped you understand some of the most common reasons why a chainsaw stops working and given you some good ways to deal with each one.

Photo of author

Charlie Bass

Charlie has been a mechanic for over 25 years and has worked on everything from small engine gardening equipment to huge diesel-electric mining haul trucks, trains and even aircraft. This broad range of industry experience gives him a unique insight into almost anything mechanical especially with an engine, including gardening and landscaping equipment. He currently owns his own mobile mechanic business and lives with his family in Australia.

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