Chainsaws are powerful tools, and once they start cutting, they make quick work of large hard logs. When everything is working as it should, your chainsaw model should have no trouble cutting through green wood, dry wood, or even damp wood. But things don’t always work the way they should, and sometimes you will have a smoking chainsaw.
The first time I saw what I thought was blue smoke coming off a gas chainsaw, I thought for sure it was going to explode. Turns out it wasn’t that big of a deal, and after killing the engine and running some extra maintenance, I was able to get it working again. But with everything that can go wrong with a chainsaw, the smoking chainsaw engine had me shaken, and I took the time to learn what I could about what to do with a chainsaw smoking while cutting.
Why Do Chainsaws Smoke?
There are tons of reasons you may see wisps of smoke rising from modern chainsaws. While exhaust smoke is not visible, you may see smoke near the engine or the blade or where the contact is happening with the wood. The issues of chainsaw smoking can be quickly troubleshot, but first, you should kill the engine and set the saw down to cool momentarily.
After it is safe and comfortable to handle the chainsaw, you can look for the specific problem or perform your usual maintenance and see if anything is unusual.
Dull or Ill-Fitting Chain
A common cause of white smoke is when chainsaw tension is incorrect. When tightening the chain with a chainsaw chain adjuster tool, you need to make sure there is no room for the bar to slide but that the chain has room to move. Chainsaw chain tension can either be too tight and put extra stress on the chain or too loose, and then chainsaw chain tension can result in the chain slipping off the bar and creating excess friction. Either way, chainsaw chain tension can cause chainsaw blade smoking unless perfect tension is maintained.
A blunt chainsaw chain will be dull and create more friction during cutting, and a smoking chainsaw chain could result. Often an unsharpened chainsaw chain will create a dust of wood, and this may resemble smoke and may eventually turn into smoke if the unsharpened chainsaw chain isn’t replaced. You can replace old and damaged chains or sharpen and adjust dull chains.
Lubrication Issues
Proper oiling for the chain bar and chain is important to prevent your chainsaw blade from smoking. Your guide bar oil reservoir should always be topped off whenever you take a break or need more lubrication. If the oil dries or is flung off the blade, then you may see your chainsaw chain-smoking and need to relubricate or face irreparable damage.
Manual lubricants are short-term fixes, and your chainsaw bar oil reservoir should always be full with the correct chainsaw bar lubrication. Tacky or thick oil will not lubricant the chain evenly and can cause grime and friction build-ups. Chainsaw lubrication oil that is too thin may be flung off the blade at high speeds or as temperatures increase and not lubricate against friction for very long. Chainsaw smoke is likely if there is no bar oil on your chain.
Engine Issues
Black smoke is common with engine issues, either having to do with the ratio of the gasoline mixture to the ratio of oil or with a dirty, clogged air filter. Chainsaw users that do not use the correct ratio of oil in the mix of gasoline will see smoke as soon as the engine fires up. You can adjust the fuel ratio and refill your engine to prevent more problems.
Cleaning the filter and removing debris and grime from around the engine components can keep your machine running better. If the chainsaw air filters get clogged, it can result in your chainsaw overheating. If an electric chainsaw smokes from near the engine, that is the air filter and not a fuel issue.
An electric chainsaw smokes from metal friction, too, so make sure the guide bar oil reservoir is full to avoid any engine issues.
High-Friction Cut
Sometimes the wood we are trying to cut is too hard for our current saws capabilities. Where the chain isn’t sharp, or the wood is extremely dry, or even frozen friction may cause smoking, and that smoking may persist even after the engine has been killed and the blade removed from the cut. Lumber is wood, and wood is combustible, so wood dust and other particles that get too hot could catch fire.
There are also times when buried metal or stone is stuck in wood or unseen under a cut, and these can also create intense friction that results in heat, smoke, and long-term damage. Make sure to clear cutting spaces before chopping, and keep an eye out for hidden obstructions. Proper maintenance with sharp teeth, the right blade for a harder wood type, and even lubrication will prevent excessive friction and smoking.
Types of Smoke from Chainsaws?
Smoke can come from several areas of the chainsaw, and each part means a different cause of the smoke and a different potential damage to your machine and injury to yourself. If your bar is smoking, it is most likely a chain or guide bar issue. If you see dark smoke billowing from the engine area, it could be a dirty air filter or a bad fuel-to-oil ratio. Sometimes the wood itself will start to smoke as you chop it, and that also needs to be dealt with immediately.
| Smoke Location | Cause | Danger |
| Bar Smoke | Not enough lubrication or wrong bar oil | Overheating and damage to mechanical and chainsaw bar parts |
| Engine Smoke | Dirty air filter and wrong oil to fuel mixture in the fuel tank | Engine failure and potential injury |
| Lumber Smoke | No lubrication, dull chain, and wood that is too hard for your chainsaw | Fire risk and broken chain or a bent guide bar. |
Bar
The bar will smoke if the chain isn’t sharp enough or installed correctly. As you can imagine, a chain on a chainsaw moves very quickly and can create chain friction. That friction can become greater if the chain tension is incorrect or if the chain is old and can slip along the bar. Forceful friction can build up and produce more heat especially if the wrong bar oil is used. A lack of oil can also cause increased friction on a chainsaw bar and additional smoking.
Engine
Air filters that have become clogged and issues in the fuel tank are the causes of black smoke around the engine. A hot engine can be scary and may burn you since that’s closer to where you hold than the saw. Make sure to kill the engine and put the saw down if you see engine smoke. Wait til it cools, and then inspect the air filter and fuel tank for dirt and impurities that might be causing the smoke.
Lumber
As lumber gets cut, there is a good chance if it is hot and dry that, it will smoke. The chance of lumber smoking increases if the chain is dull or if there is insufficient oil. Sometimes it is not a lack of oil, but simply the wrong oil causing the friction problems, and adjusting your lubrication should fix that catalyst. If smoking occurs, stop cutting and wait until the sawblade and wood have cooled before continuing to cut in order to prevent other smoke-related issues.
What to Do When Chainsaws Smoke?
When your chainsaw starts to smoke, you will want to act quickly. In a matter of seconds, a serious life-altering injury can occur when using a chainsaw, so when something unexpected happens, you should react immediately. Kill the engine and put the saw down, and let all smoke clear until your visibility is good. Once the saw is cool enough to handle, investigate the areas that were smoking.
If the blade is smoking, inspect the chain and bar for the culprit. Add oil to the bar and sharpen the teeth of the chain to make sure you have full cutting power. Add bar oil to the reservoir and make sure it is the correct tackiness for the job and weather conditions. If the chain and blade seem to be the correct tension, you can continue cutting.
If case your engine has started smoking, you can do a few things. First, pop open the case around the air filter and check that it is clean and unclogged. If it can’t be cleaned or it is looking old and damaged, replace the air filter for better performance. If it’s not the filter, you will need to check the fuel tank.
Chainsaw fuel needs to be mixed with oil at a ratio of 50:1. That is 50 parts fuel to 1 part oil, and if you do a different ratio, you will see black smoke. Replace the fuel with the correct mix to fix that issue. If there is water or dirt in the fuel tank, you may also get black smoke.
Fixing this quickly is important as other parts of the internal engine could become damaged and result in costly repairs. Keep your chainsaw maintained at all times to avoid spontaneous smoking and potential chainsaw damage.