Chainsaw Smoking When Cutting

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Written By Janine Clarke

I am Janine Clarke AKA Equipment Girl, a nerdy girl with an unhealthy knowledge about power tools and gardening! You can contact me here.

Your chainsaw smoking when cutting wood is clearly not a good sign. Your chainsaw chain is designed to cut through wood without issue, so if your chainsaw is smoking, then there’s obviously something that matters.

Thankfully, a smoking chainsaw doesn’t necessarily mean it’s come to the end of its life. There may still be hope for it yet.

Below, we’ll talk more about the three main areas responsible for chainsaw smoke, why your chainsaw is smoking to begin with, and how to fix the issue.

Ready to find out more? Then let’s dive in!

Why Chainsaw Smoking Is A Bad Thing

If your chainsaw is smoking, it isn’t always a bad thing. New chainsaw users don’t realise that your chainsaw engine/chainsaw chain smoking isn’t necessarily a sign of a problem. Light smoke is to be expected when a chainsaw is creating so much friction against wood as it works, right?

The problem occurs when smoking is excessive.

You’ll know the difference between normal smoke and excessive smoke the more you use your chainsaw, but there is one sure sign that the root cause is problematic: if the smoke is accompanied by overheating.

Allowing your chainsaw to overheat is not a good idea, because it can cause irreparable damage to the chainsaw blade, engine, and chain. Problems with your bar and chain area are never good, so that ought to be fixed as quickly as possible.

Producing smoke and heat is a sign that something is wrong, and it’s usually to do with specific areas on your chainsaw…

Which Areas Of The Chainsaw May Be Responsible

If you notice that excessive smoke is coming from any of the three areas below, then there’s probably a problem:

  • Chainsaw chain and chainsaw bar area
  • Fuel tank
  • Chainsaw engine

What’s causing these three areas to produce smoke might be different, but below we’ll talk you through the most common causes of each one so you know what to check and how to fix it.

Chainsaw Chain Smoking

If the chainsaw smoke is coming from the chainsaw chain, then it can be for any number of reasons. The most common four, though, are:

  • poor lubrication because there are problems with the guide bar oil reservoir where bar oil can’t keep things oiled well enough
  • chain is dull
  • chain tension slightly off
  • excessive friction between chainsaw bar and chain

Chainsaw Chain Lubrication Due To Bar Oil Reservoir

Low or no bar oil lubrication will cause the chainsaw smoke to come from the chain because of the increase in friction when cutting wood. If the chain isn’t well oiled, then there will be too much strain on the chainsaw chain, and you’ll notice overheating.

Thankfully, the fix is easy.

First, check the bar oil reservoir to make sure that it’s not empty. If it is, fill it, being careful not to use too much oil. Whilst excessive oil won’t cause smoke, it is unnecessary and a waste of good bar oil.

If there’s bar oil in the oil reservoir, then the problem is likely due to the oil pump not working at all, or not allowing enough bar oil to pass through to lubricate the chain and blade regularly. Test this by running the chainsaw full throttle two inches from some cardboard. If the light colored surface afterward isn’t darker with small dots or a light line of oil, then you can confirm that the oil reservoir is blocked and enough oil isn’t passing through.

To fix a blocked oil reservoir, head to the guide bar oil reservoir area and remove the bar. There should be a small hole running from the bar side to the chain grooves. Clear this of any debris, sawdust, or dirt, using compressed air, and then put everything back together and test that the oil is reaching your chainsaw blade and chain.

This should stop the smoke.

Chainsaw Chain Dull

Another reason for chain smoke is a dull chain, again, because of the excessive friction caused by having a chain that isn’t sharp enough to cut through the wood.

To fix this, you’ll need to sharpen the chainsaw chain using a file. Look at the teeth along the chain and ensure they are even on both sides. You can use an adjustable wrench to measure this.

Any taller teeth will need to be filed to the same size as the others, making them even, and sharpened at a 30-degree angle for best results. Only ever file in one direction, or else the teeth will be damaged.

Make sure you stay on top of keeping your chain sharp regularly through maintenance to avoid smoke again.

Chainsaw Chain Tension

If the chainsaw chain isn’t set to the right tension around the bar (check the bar and chain area for a tension screw to tighten or loosen as required), then it can cause a smoking chainsaw.

If tension is too tight, then the chainsaw chain will be placed under too much strain as it works, and if it’s too loose, then it can’t operate as it should. This can lead to smoking.

To fix it, you simply need to tighten or loosen the tension screw to allow the chain to fit over the bar snugly, without being too tight. Get this right, and it should no longer be overheating.

Excess Friction With Chainsaw Bar

If the chain bar area is experiencing friction, then this can cause smoke because the chain bar area is one of the most integral parts of your saw. Chainsaws require the chain (the cutter) and the bar (the guider) to work in conjunction with one another to get the perfect cut. If there’s excessive friction, though, it can smoke because the chain constantly rotates around the bar.

The two may rub against each other too much and cause overheating and smoking if there’s a pinch in the chain groove. Inspect the bar slowly and look out for a narrow area of the chain groove. If you notice it, open up the track and stretch out the chain to sit on the track evenly without a pinch. This will stop the bar and chain from rubbing and, therefore, stop the smoke.

Fuel Smoking

If you notice that the fuel seems to be smoking in the tank, then you’ll probably see problems at the exhaust port. The two most common reasons for smoking fuel are:

  • wrong fuel mix/fuel oil ratio
  • contamination with the fuel mixture

Wrong Fuel Oil Ratio

Don’t get the correct ratio when mixing your fuel and oil, and you’ll notice black smoke from your exhaust almost immediately. This is a sign that you’ve used too much oil, creating a rich fuel mix that smokes.

To fix the issue, simply pour out the old fuel and mix together a new mixture in a separate container with a tight-fitting lid. Typically, most chainsaws use an oil to fuel mix of 1:50, oil:gas. Check your user manual to make sure that’s right for your model.

Regardless, mix the exact amount of oil and gas in the container as instructed, pouring the oil in first, followed by gas, and then swirl them together to mix. Pour this into the chainsaw tank, and it should now operate without the smoke.

Contamination In Fuel Tank

If there’s contamination from dirt, debris or water in your fuel, then it can cause smoking. Check the solution to ensure there aren’t any contaminants. If there are, you’ll need to dump the fuel and mix together another batch of oil and gas to go again.

Whilst you’re there, you should clean out the tank with hot soapy water, rinsing it with another round of hot water, before allowing it to dry fully. Once fully dry, you can then add the new contaminant-free fuel to the machine and try again. This should stop the smoking.

Engine Smoking

And, finally, if the smoke you’re noticing is coming from the engine or chainsaw body, then this is likely because of:

  • a clogged air filter
  • or idle speed issues

Air Filter Clogged

If an air filter is blocked, then your machine might smoke because of overheating. If the proper air isn’t being introduced to the combustion chamber, then the fire may still burn, but the excessive heat can cause overheating and smoke.

Simply take out the old air filter and clean it of any sawdust or debris. As mentioned earlier, compressed air can be a great tool for this sort of cleaning. Once it is clean, put the air filter back in place and you should notice that the overheating and smoke have stopped.

Idle Speed Issues

If there is a problem with smoking at low speed when you’re operating the chainsaw, it may be because the idle speed adjusting screw isn’t set right, allowing the chainsaw to operate too fast too quickly, causing smoke.

You should alter this when in operation, so be extra careful. Then, locate the adjusting screw and turn it clockwise until the speed slows. Then turn it backwards 90 degrees and increase the throttle to make sure it accelerates evenly. This even acceleration will stop the chainsaw from overworking and overheating.

Final Thoughts

There are many reasons why your chainsaw might smoke whilst cutting, but none of them are particularly serious. So long as you troubleshoot the issues listed above, most times, your chainsaw will be back to cutting normally again.

If the smoking continues or the smoking is with an electric saw, then it might be the case that the chainsaw is on its last legs. Either way, if you’ve tried all the fixes above and it’s still smoking, stop using the chainsaw immediately until it’s been looked at by a professional who may be able to diagnose the issue and fix it.

If you found today’s article helpful and the problem is resolved, though, then congratulations! Your chainsaw should smoke no more, and with regular maintenance of the issues presented today, it may never smoke again!