How-to guide: replacing a chainsaw chain

Replacing the chain on your chainsaw is something that is sure to need doing. Be prepared with our instructions and video guide.

A STIHL MSA 120 cordless chainsaw on a workbench, with someone inspecting it

Replacing a chainsaw chain: safety first

Ensure that the chainsaw is switched off and cannot start up during assembly:

  • For a cordless chainsaw, remove the battery and apply the chain brake.
  • For an electric chainsaw, remove the plug from the socket and apply the chain brake.
  • For a petrol chainsaw, switch off the engine and turn the combi lever to 0. Apply the chain brake.
  • Always wear work gloves made from robust material.

Cutting attachment installation

The method for fitting a cutting attachment is the same for electric, cordless and petrol chainsaws. The only difference is in the individual steps related to the tensioning device with which your STIHL chainsaw is equipped. We also have an article with more information about chainsaw chain and bar systems.

Close-up of a saw chain being held by someone wearing gloves

Replacing a chain on a chainsaw with Quick Chain Tensioning

Fitting the cutting attachment is particularly quick and convenient on STIHL chainsaws that have Quick Chain Tensioning, and requires virtually no tools – just a flat head screwdriver.

Here's how it works:

Step-by-Step Video: Quick Chain Tensioning

Replacing a chain on a chainsaw with side-mounted chain tensioning

The side-mounted tensioner is widely used in many electric, cordless and petrol chainsaws. It offers convenient access to the chain tensioning components and also reduces the risk of contact with hot engine components. 

Here's how it works:

Step-by-Step Video: Side-mounted chain tensioning

Chainsaw tension: Front chain tensioning

The tension adjustment screw is usually located on the side, however there are a few models, where it is located on the front. The method for adjusting the tension is the same as for side-mounted tensioners.

Step-by-Step Video: Frontal chainsaw tensioning

After replacing the chain: topping-up chain oil in your chainsaw

All petrol, cordless and electric chainsaws must be filled with high-quality chain oil to ensure that the saw chain and guide bar are always lubricated and cooled. Doing this reduces wear on the chain and extends the service life of your cutting attachment. The process is the same for chainsaws of all drive types. If you have a petrol tool, you should top up the chain oil every time you fill up with petrol. For cordless and electric chainsaws, check the tank regularly and refill it as needed. Some STIHL chainsaws have a window on the tank that helps you to check the fill level.

Fuel caps

STIHL chainsaws either have a conventional screw-on fuel cap or a tool-less fuel tank cap. The process described here is for using and replacing a screw-on cap; if you have toolless tank caps, we have put together separate detailed information about opening and replacing tool-free fuel caps.

How to fill your chainsaw with chain oil:

A combination canister on a bench between containers of STIHL MotoMix and BioPlus chain oil

Petrol chainsaw fuel mix

Your chainsaw needs the right fuel mix and filling process to keep it performing at its best and to ensure your safety.

Man kneeling on the floor and filling STIHL fuel into an orange canister

Choosing the right fuel and oil mix

Your chainsaw runs on a mix of petrol and engine oil, and its important to get the mix right. We take you through the mixing and filling process with all the information you need.

Safety when refuelling

  • Petrol is extremely flammable. You should always maintain a safe distance from any naked flames when refuelling your chainsaw, avoid spilling fuel and do not smoke in the area. Chainsaw refuelling should always be done at least 3 metres from the working area in which you will be starting your chainsaw.
  • Switch the engine off completely before filling the fuel tank; you should not refuel while the motor is hot.
  • Open the fuel cap carefully to allow any overpressure to dissipate gradually and to ensure that no fuel sprays out of the tank.
  • You should only ever refuel a chainsaw in a well-ventilated area.
  • Make sure that you do not spill any fuel on the tool or your clothes. If you do spill fuel, you must immediately clean the chainsaw and change your clothes.

Your STIHL dealer is always happy to support you by preparing your chainsaw for use.

After replacing and fuelling, you're ready to go: Our article tells you how to start your chainsaw.

Summary: replacing a chainsaw chain and other regular maintenance

  • Switch off the engine. For cordless models, remove the battery and for electric models, unplug the device. Apply the chain brake
  • Wear gloves made from cut-resistant material when replacing your chainsaw chain
  • The methods for fitting a cutting attachment are the same across electric, cordless and petrol chainsaws, though the method for replacing the attachment depends on whether your STIHL chainsaw has Quick Chain Tensioning or side chain tensioning
  • Refuel your chainsaw on a clean, level surface
  • Do not fill the chain oil or fuel tank right to the top