Chainsaws can sometimes emit smoke for various reasons. This can be very confusing for new chainsaw users, as they don’t know whether this is normal or not. But what is the answer?
Are chainsaws supposed to smoke? No, they aren’t. It isn’t normal for a chainsaw to smoke, but if it does happen it can be the result of the chainsaw overheating, the fuel mix containing too much oil, or the chain either not being sharp enough or not getting enough lubrication.
In short, a smoking chainsaw is a sure sign that something isn’t right. Of course, there is more to it than that, and understanding the cause behind the smoke should be the first step to fixing the problem.
Why do chainsaws smoke?
As I’ve said before, a chainsaw can smoke for a number of reasons. The easiest way to determine the cause is to check where the smoke is coming from. Once you have found the source, the list of possible causes can be narrowed down and you can get to fixing them before your chainsaw gets damaged.
You’ll find a list of common symptoms below, see if any of them applies to you!
The chainsaw’s chain is smoking
This one is easy to differentiate from the others, because only the chainsaw’s chain is smoking, and it only starts after you have done some cutting with it. In short, for some reason the chain is generating too much friction while cutting which causes it to emit some smoke.
The smoke can be the result of some of the wooden scraps generated from cutting literally burning away due to the heat generated by the chain, but if the wood you are cutting is wet, the water contained inside can also evaporate. This is especially easy to mistake for smoke in extremely cold weather.
But why does the chain generate so much heat? There are two main reasons to this:
The chain isn’t sharp enough
The first case usually happens if the chain you are using is older, and hasn’t been sharpened in a while. If the chain is dull, it will need a lot more time to cut through wood than it would under optimal conditions, generating a lot of needless friction in the process.
This will warm up both the wood you are cutting and the chain itself, resulting in the smoke I’ve mentioned earlier.
It’s easy to tell if your chain isn’t sharp enough. Normally, just placing the chainsaw on a piece of wood should be enough for the blade to bite into it, without any additional force applied on your part.
Another thing you can check is the size of the wooden scraps that are left over from cutting. Normally they should be bigger scraps, but if your chain is dull it will only leave wooden dust behind.
You can fix this problem by sharpening the blades on your chain. The easiest way to do this is buying one of the chain sharpeners sold by most chainsaw manufacturers. Alternatively, you can buy a new chain if you have decided that your current one is beyond saving.
The chain isn’t getting enough lubrication
If your chain is sharp enough but it’s still smoking, it most likely isn’t getting enough lubrication. First things first, you should check if the chainsaw has enough bar oil in its tank. If it’s empty, you should top it off and the problem should go away.
In some cases however, the bar oil isn’t getting onto the guide bar or isn’t getting distributed along the chain properly.
To check if this is the case, put a piece of paper on the ground. Now start up your chainsaw, and hold the edge of the guide bar above the paper while rotating the chain. If everything is working properly, you should see a steady stream of small oil drops appearing on the paper.
If this isn’t happening, then for some reason the bar oil can’t flow through the guide bar properly. The most common reason to this is that the channels responsible for distributing the oil got clogged by wooden scraps or some other form of fine dust.
If you remove the chain from the guide bar, you should see a thin channel on it right below where the chain was previously. Find something that fits in there, like a small screwdriver or maybe some paper clips (whatever works really) and see if you can pick any wooden dust out of it.
If this channel is clogged, the bar oil won’t be able run through it freely so make sure to remove any wooden scraps and dust from it.
If you cleaned the oil channel on the guide bar and the problem still persists, it’s possible that the chain isn’t getting any oil to begin with. To check if this is the case, you’ll have to remove the guide bar from your chainsaw because the oiler is located below it. Check your user manual if you aren’t sure what to look for – it can be slightly different for every manufacturer.
Next, fire up your saw and start running the engine – you should see a steady stream of oil flowing from the oiler port. If this isn’t the case, make sure that the port isn’t clogged by wooden scraps. If it was indeed clogged then cleaning it should fix the problem.
If the port isn’t clogged and the oil still isn’t flowing, then the oiler mechanism is most likely broken. Unfortunately, fixing that is outside of the scope of this article – I’d recommend taking your saw to a nearby service center.
Black smoke is leaving the exhaust port
This is usually the result of the fuel mix having too much oil in it. Most chainsaws nowadays use the 1:50 oil/fuel mix, but always check your user manual to make sure as it can be different for some chainsaws.
This condition isn’t that dangerous to your chainsaw, but it may have performance issues and of course it will use more oil and fuel than it should.
To fix this problem, first drain the fuel mix with the incorrect oil ratio from the tank. Next, prepare a fuel mix with the correct ratio and put it into the chainsaw’s fuel tank. After running the chainsaw with the proper fuel mix in it for a few minutes, the black smoke should go away.
Alternatively, you can try “fixing” the gas that you previously drained from the tank by adding more fuel to it. But this requires you to know the exact oil ratio you used previously, so that you an calculate the exact amount of fuel you need to add.
If you aren’t sure about it, then I wouldn’t risk it if I were you – not having enough oil in the fuel mix will ruin your engine.
The chainsaw is smoking from the engine
This is usually the sign of some more serious issue – one that can ruin your chainsaw if it doesn’t get fixed. There are two main ways this problem can present itself:
The chainsaw is smoking on startup
If the chainsaw starts smoking right from startup, it’s usually a sign that the engine is running lean. This means that it isn’t getting enough fuel for the amount of air it’s taking in.
This will cause problems in the long term as it can overheat your engine, eventually ruining it. To fix this, you should adjust the chainsaw’s carburetor to provide more fuel to the engine.
The process of doing this is a bit different for every chainsaw brand, but it’s usually done with a screwdriver. Check your user manual to see how it’s done. Also, check if they have any recommendations for the optimal settings for various temperatures. This could save you a lot of time compared to figuring out what works on your own.
The chainsaw starts smoking during usage
If this happens, then your chainsaw is most likely overheating. This is a serious issue, as it can ruin your chainsaw in a very short amount of time.
This can be the result of a number of things, but the main ones are:
- Insufficient oil in the fuel mix
- Clogged exhaust port
- Clogged air filter
Also, the chain not being sharp enough or simply cutting a tree that is too big for your saw can also be contributing factors.
This topic is too big to fully cover here but I’ve previously written a detailed article about it. You can check it out here. It covers the most common causes for a chainsaw overheating, and ways to prevent it from happening.
The motor of an electric chainsaw is smoking
If the motor of an electric chainsaw starts to smoke, it’s a sure sign that you have pushed it a bit too far. If this ever happens, you should stop the chainsaw immediately and let it cool down for a bit.
The problem is, by the time you notice this it’s usually too late. If the chainsaw stops working while the motor is smoking and it won’t start up again, then the motor is most likely fried for good.
If you have managed to stop it in time, you should check if there are any circumstances that may have caused the motor to overheat in such a way. Check if the chain is getting sufficient lubrication, and make sure it’s sharp enough.
Also, since electric chainsaws are usually designed for smaller workloads, it’s possible that whatever you tried to do was a bit too much for it. If this is the case, buying a bigger saw might be your best bet.
And with that, we have arrived to the end of this article. I hope I was able to help you, and as always, feel free to message me if you have any kind of question or recommendation!