Chainsaw Smoking When Cutting? Resolved

It’s easy to forget how much punishment we give our chainsaws, thrashing the chain and pushing the engine. With this intensity of work, even the best chainsaws show us when something is wrong, and if you ignore these signs it can prove to be a very expensive mistake.

Is your chainsaw smoking when cutting? If so you need to down-tools and find the root cause and fix it quick…so let’s get to the bottom of why your chainsaw is smokin’…

Why Does My Chainsaw Smoke When Cutting?

There are several reasons why your chainsaw is smoking when cutting wood, the most common causes include:

  • A Blunt Chainsaw Chain
  • Too Much Oil in the Fuel Mix
  • Bar Oil Reservoir Is Empty of Blocked

No matter what the cause, you need to fix it before any permanent damage happens. In this article, I will diagnose 6 reasons why your chainsaw is smoking and provide the fix so that you can get back to work and finish the job.

There is a distinct difference between a smoking chainsaw chain and a smoking engine. If the smoke is originating from the bar or chain whilst cutting wood, then it is most likely the result of some form of chain friction. So let’s start there.

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Chainsaw Chain Smoking

The chainsaw chain is the hardest working component on your chainsaw so it’s no surprise to have it show signs of stress. Your chainsaw smoking when cutting is a sure sign the chain needs a close inspection.

Chainsaw Chain Not Getting Enough Lubricant

If you are getting smoke from the chain when cutting it will most likely be low or no bar oil reaching the chain bar. Here’s a step-by-step diagnosis:

  1. Check the oil level of the chainsaw bar oil reservoir. If its empty refill it.
  2. If the oil reservoir is full, inspect the chain to see if it is coated in a thin layer of oil. If you cannot see oil, gently pull the chain away from the bar and look for signs of oil between the bar and the chain.
  3. If neither of the above methods work, then hold the chainsaw, holding the end of the blade about 2 inches away from a piece of brown corrugated cardboard, and full throttle the chainsaw. You should see an oil spray come of the chain and wet the brown carboard. If there is no oil spray the oiler reservoir will be clogged.
  4. To unclog the oiler, take off the bar and you will find a small hole running from the side of the bar through to the bottom of the chain groove. Clear any sawdust that may have gathered in the hole. Use a thin piece of wire or a can of compressed air. 

Chainsaw Blunt or Dull

A blunt chainsaw will start to kick out smoke as it generates friction against the wood cutting surface.  With experience, it’s easy to tell when your chain is getting dull.

  • A sharp chainsaw chain will cut out large chips of wood and cut smoothly.
  • Blunt chains with dull teeth will gum their ways through the wood and kick out fine wood dust.

Not only will a blunt chain cause smoke on dry wood it can also cause steam when cutting wet wood in cold conditions.

Don’t sharpen your chain when it’s blunt, sharpen it after every gas tank to prevent it from getting blunt. This will reduce fatigue and give you a much faster and cleaner cut.

Chainsaw Bar Friction

If you experience a pinch in your chainsaw bar when cutting timber, it’s possible that this pinch causes a narrowing of the chain groove. This can result in the track the chain passes through narrowing and creating excessive friction, leading to overheating.

Inspect the bar and look out for a narrowing of the groove. Use a flat head screwdriver to open out the track, making the chain groove equal width to the original groove on the rest of the chainsaw bar.

Chainsaw Engine Is Smoking and Overheating

If the smoke is coming from the engine or within the body of the chainsaw then I suspect it will be a bad oil to gas ratio or a problem with the air filter and engine cooling. So let’s now focus on that in more detail.

Black Exhaust Smoke Wrong Fuel to Oil Ratio

If you have a thick black smoke kicking out of your exhaust it’s most likely a result of using an incorrect oil to fuel ratio in the fuel mix. Most modern chainsaws use a 1:50 ratio of oil to gas. If you add too much oil the engine smokes.

The fix is easy enough. Simply drain your fuel tank and refuel using an accurate 1:50 oil to gas ratio.

Chainsaw Air Filter Blocked or Clogged Up

The working environment of a chainsaw is dusty, to say the least. This means your chainsaw air filter can be a great ally in protecting the engine from dust contamination. In the process, your air filter surface will gradually build up with dust until clogged.

When very little or no airflow is moving to cool the engine, it can lead to overheating and in extreme cases smoking.

Simply remove the air filter and replace it with a new one. Alternatively, you can simply knock the sawdust off by hand, brush it off, or use compressed air to blow the dust off before re-installing it back in your chainsaw.

Why Is My Electric Chainsaw Smoking?

A smoking electric motor is a bad sign.

Stop working immediately and allow the chainsaw to cool down. Perform all of the previous checks, oil, bar rails, air filter. Try to start the chainsaw again. If it smokes, then the chances are you’ve metaphorically smoked it by pushing it too hard.

A smoking motor can be caused by several mechanical or electrical failures resulting in moving parts meeting resistance and building significant friction.

The more you power the motor the more resistance you create which ultimately leads to the motor smoking. The most likely cause will be worn motor brushes or some other similar actuator. In this case, there is no simple DIY fix, I would recommend you take the machine to an authorized repairer.

What Happens If You Overheat A Chainsaw?

If you are unfortunate or crazy enough to run your chainsaw until it overheats then it is possible there will be irreparable damage to the cylinder head and pistons.

Let the chainsaw engine completely cool down and then try to restart it. If it runs smooth, then carry on using it and take it as a warning.

If the machine is toast, you can either scrap it and buy a new chainsaw. Or take it to an engine repair center where they can either recondition or replace the engine components affected. But in practice, this may cost more in part and labor than buying a new chainsaw.

Chainsaw Smoking When Cutting? Resolved

Hopefully, by now you have your fix, your problems are solved, and you are equipped to get back out there and give your smoking chainsaw the care and attention it deserves.

If your chainsaw smoking when cutting, remember to check the lubrication, sharpen your blade regularly not just when it’s dull, and make sure your fuel to oil ratio is 1:50 oil to gas…and I’ll see you next time.