Smoke coming from your chainsaw can be alarming. You may see smoke coming from the bar when cutting or coming from the exhaust. The last thing you want to do is damage the chainsaw which can result in a large repair bill.
A chainsaw is smoking due to increased friction between the bar and chain, too much oil in the fuel mixture, water in the fuel system, or a plugged air filter.
Be careful working with your chainsaw. Take all safety precautions listed in your operator’s manual. This includes waiting for the engine to cool and removing the spark plug boot before making repairs.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
Chainsaw is Smoking from the Bar & Chain When Cutting
If you find your chainsaw begins smoking when you cut, look for items that can cause friction to occur between the bar and chain.
This may be due to a dull chain, poor lubrication, or a chain that won’t move freely around the bar.
Dull Chain or Incorrectly Sharpened Chain
Check out the chain to make sure it is sharp. A dull chain will not cut wood efficiently and may begin to smoke.
The increased pressure applied to the bar to cut wood causes metal-on-metal friction creating heat and smoke.
Look for these signs indicating the chain is dull:
- Needing to apply increased pressure on the bar to make a cut.
- Fine sawdust is created when making a cut.
- Chips or damage to the chain.
- Worn teeth and rakers.
You can sharpen the chains yourself. If you don’t have experience sharpening chains, I highly recommend having a professional sharpen them for you. A chain that isn’t sharpened right can be a serious safety hazard.
Lack of Bar & Chain Oil
When the chainsaw bar and chain are not sufficiently lubricated, friction will build often resulting in smoke.
A reduction in proper lubrication could be due to running out of oil in the tank or having a clogged oiler. Depending on your saw, you may have an adjustment screw that controls the amount of oil released from the tank.
Fill the bar and chain oil tank if it is low on oil or empty.
To check for sufficient oil on the bar, run your chainsaw at about 1/2-3/4 throttle. What you are looking for is a line of oil coming off the bar while holding it less than a foot off the ground.
If you aren’t getting good lubrication, make sure the bar is in good condition and the oil channel isn’t blocked. Replace a worn or damaged guide bar and clean the oil channel if needed.
If your model chainsaw has an adjustment screw, adjust the screw to allow more oil to coat the bar and chain.
It is good to get into the habit of refilling the bar and chain oil every time you fill your chainsaw with fuel. However, if the oil you are running in the saw is too thin, you may go through oil at a faster rate and have to check and refill it more often.
Wrong Type of Bar and Chain Oil
Using a bar and chain oil that is too thin may cause bar and chain damage and increased friction causing smoke to come from the bar. An oil that is too thin may not stick to the bar and chain and instead get slung off of it.
Make sure you are using a premium bar and chain oil like these oils from ECHO, Husqvarna, and STIHL.
Chain is Too Tight
The chain will loosen as you use it so you’ll need to check it regularly and tighten it. However, if you tighten the chain too much, it will not spin freely around the bar and increased friction will result in smoke.
Adjust the chain tension on a chainsaw:
- Remove the spark plug wire.
- Unlock the chain brake.
- Loosen the bar retaining nuts that hold on the cover over the clutch and chain brake.
- Hold the nose of the bar up.
- Turn the tensioning screw counter-clockwise to loosen the chain and clockwise to tighten the chain.
- Once you achieve the correct tension, tighten the bar retaining nuts while continuing to hold the bar nose up.
You want the chain to sit securely around the bar, but still able to move easily. You don’t want it too loose that it hangs from the guide bar.
Chainsaw is Smoking from the Engine and Exhaust
When your chainsaw smokes while running, you will need to look at airflow issues including a plugged air filter or a problem with the fuel mixture.
Plugged Air Filter
Operating a chainsaw is a dirty job. Sawdust and small wood chips are tossed into the air.
An air filter is used on your chainsaw to ensure the engine receives clean air. The filter keeps dirt and sawdust from entering the carburetor throat and wearing on the engine.
If you use your chainsaw sparingly, replace your air filter annually and check it before each use. If you use the saw regularly, check the filter frequently and replace it when it becomes very dirty or damaged.
If you don’t regularly check and clean the filter to ensure it is in good condition, it can become so clogged that air isn’t able to pass through it.
The fuel mixture will run rich and smoke. The engine may eventually shut down due to a lack of air.
Too Much Oil in the Fuel Mixture for a 2-Cycle Chainsaw
2-cycle chainsaws require a gas and oil fuel mixture. Using more oil than this can cause the engine to begin smoking.
Once you realize the smoke is coming from the wrong fuel mixture, remove the fuel and fill it with fresh fuel with the correct gas-to-oil mix.
This won’t normally cause long-term damage. Running too much oil may cause running problems due to an increased buildup of carbon in the exhaust.
Note: There are some chainsaws with 4-cycle engines on the market today. These engines do not require gas and oil to be mixed.
Water in the Fuel System
Water in the fuel can cause white exhaust smoke. Water is corrosive to the fuel system and engine.
Instead of trying to figure out a way to save fuel and remove water, it’s best to empty the fuel tank and refill it with fresh fuel. Check out this guide on the right fuel mixture for your chainsaw.
Add in a fuel additive like Sea Foam Motor Treatment to help remove moisture and clean the fuel system. Start the saw and allow it to run to get the treated fuel through the system.
Still Having Troubles With Your Chainsaw?
As a chainsaw owner, you’re going to run into problems with it occasionally. This is true of all chainsaws.
To help you quickly identify the cause of your problem and how to fix it, I’ve put together a handy reference guide.
You will find charts with problems and solutions to many common issues along with links to information in more detail.
Check out Common Chainsaw Problems for help solving problems with your equipment not starting, the chain not turning, the engine dying, a loss of power, and more.