Replacing a Husqvarna chainsaw chain takes 10 to 15 minutes once you know the steps

A dull or damaged chain is the most common reason a chainsaw stops cutting cleanly. Replacing it yourself costs far less than a repair shop visit and requires only basic tools you likely already have. On a Husqvarna, the process is the same across most models: loosen the side cover, slide out the old chain, thread the new one onto the sprocket, and tension it so it sits snug against the bar without binding.

You will need a socket wrench or combination wrench (usually 8mm or 10mm, depending on your model), a new chain that matches your bar length and pitch, and a flat work surface. Check your owner's manual or the bar itself for the exact chain size — this matters. A chain that is too large or too small will not fit properly and can damage the sprocket.

Key Takeaways

  • Always stop the engine, let it cool for at least five minutes, and disconnect the spark plug wire before touching the chain.
  • The chain pitch (the distance between rivets) and bar length must match your old chain exactly, or the new chain will not fit the sprocket.
  • Loosen the side cover bolts, remove the old chain, and thread the new chain onto the sprocket with the sharp edges facing forward.
  • Tension the chain so you can pull it away from the bar by about a quarter inch at the midpoint — too loose and it derails, too tight and it burns out the sprocket.
  • After 10 minutes of cutting, stop and check the tension again, because new chains settle and loosen slightly.

Gather the right replacement chain for your model

The chain size is printed on the bar itself or in your owner's manual. You need three pieces of information: bar length (usually 14, 16, 18, or 20 inches), chain pitch (most commonly .325 or .375 inch), and gauge (the thickness of the drive links, usually .050 or .063 inch). Write all three down before you buy, because a chain that is close but not exact will not work.

Husqvarna chains are sold under the Husqvarna brand and also by third-party makers like Oregon and Stihl. Any chain with the correct pitch, gauge, and link count will work on your saw. Count the links on your old chain if you are unsure — a typical 18-inch bar uses 66 links, but this varies. Buy the chain from a hardware store, online retailer, or Husqvarna dealer.

Prepare the chainsaw and remove the old chain

Set the saw on a flat, stable surface. Stop the engine if it is running. Disconnect the spark plug wire by twisting the rubber boot and pulling it off the spark plug — this prevents accidental starting while you work. Wait at least five minutes for the engine to cool. The chain and bar get very hot during use and can burn your hands.

Locate the side cover on the right side of the saw (the side facing you when you hold it). You will see two or three bolts holding it in place. Use your wrench to loosen them counterclockwise, but do not remove them completely — loosen them just enough that the cover moves freely. On some Husqvarna models, the cover is held by a single large bolt with a spring underneath; loosen this bolt until the spring is no longer compressed.

Slide the side cover toward the rear of the saw to expose the sprocket and chain. The old chain will be loose now. Lift it off the sprocket and bar and set it aside. Wipe away any dirt or sawdust from the sprocket and bar with a dry cloth.

Thread the new chain onto the sprocket and bar

Hold the new chain so the sharp edges of the teeth point forward (toward the tip of the bar). The chain has a top run and a bottom run; the top run is the one that does the cutting. Start at the sprocket and thread the chain onto the small teeth of the sprocket, working your way around. The drive links (the thick metal tabs underneath the chain) must sit in the groove of the sprocket.

Once the chain is fully seated on the sprocket, lay the bar flat and guide the chain around it. The chain should sit in the groove that runs around the edge of the bar. Make sure the chain is not twisted and that every link is in the groove. If any link is sitting on top of the bar instead of in the groove, remove the chain and start again.

Slide the side cover back toward the front of the saw so it presses against the chain and bar. Do not tighten the bolts yet — you need to adjust the tension first.

Tension the chain correctly

Proper tension is critical. A chain that is too loose will derail and fall off during cutting. A chain that is too tight will burn out the sprocket and overheat the engine. The correct tension lets you pull the chain away from the bar by about a quarter inch at the midpoint of the bar.

With the side cover loose, grab the chain at the middle of the bar and pull it upward. If it pulls away easily and snaps back into the groove, it is too loose. If it barely moves, it is too tight. You should feel a small amount of resistance. On Husqvarna saws, there is usually a small adjustment bolt or screw on the side cover near the sprocket. Turn this bolt clockwise to tighten the chain or counterclockwise to loosen it. Make small quarter-turn adjustments and test the tension after each one.

Once the tension feels right, hold the side cover firmly in place and tighten the cover bolts in a crisscross pattern (tighten the top bolt, then the bottom, then the middle if there is one). This keeps the cover from warping. Tighten firmly but do not over-tighten — you should feel solid resistance, not a grinding sensation.

Check tension after the first few minutes of cutting

Reconnect the spark plug wire by pushing the rubber boot onto the spark plug until it clicks. Start the saw and let it idle for 30 seconds. Cut a small piece of wood or a log for about 10 minutes at normal throttle. Stop the engine and let it cool for two minutes.

Check the chain tension again using the same quarter-inch pull test. New chains settle slightly during the first few minutes of use and often loosen. If it has loosened, repeat the tension adjustment. After this second check, the chain should hold its tension for the rest of its life, though you should always inspect it before each use.

Common mistakes to avoid

The most common error is buying a chain with the wrong pitch or gauge. A chain that is close but not exact will not fit the sprocket properly and can cause the saw to bind or the chain to derail. Always verify the three measurements before you buy. Another frequent mistake is over-tightening the chain. This burns out the sprocket and wears the engine faster. If you have to force the chain around the bar, it is too tight.

Some people forget to reconnect the spark plug wire after replacing the chain, which is a safety hazard if someone else picks up the saw. Always reconnect it before you start the engine. Finally, do not skip the tension check after the first few minutes of cutting. New chains always loosen slightly, and catching this early prevents the chain from derailing mid-cut.

Frequently Asked Questions

How do I know what size chain to buy?

Check the bar itself — the size is usually stamped on the metal. You need the bar length (14, 16, 18, or 20 inches), the pitch (usually .325 or .375 inch), and the gauge (.050 or .063 inch). Write all three down before you shop. If the bar marking is worn, check your owner's manual or call a Husqvarna dealer with your model number.

Can I use a non-Husqvarna chain on my Husqvarna saw?

Yes. Oregon, Stihl, and other brands make chains that fit Husqvarna saws as long as the pitch, gauge, and link count match exactly. Many people use third-party chains because they cost less. Just make sure the specifications are identical to your old chain.

What if the chain keeps coming loose after I tighten it?

The sprocket may be worn out. A worn sprocket has shallow teeth that do not grip the chain drive links as well, causing the chain to slip. If the chain loosens within a few minutes of tightening, inspect the sprocket for flat or rounded teeth. If it looks worn, the sprocket needs replacement — this is a job for a repair shop.

How tight should the chain be?

Pull the chain away from the bar at the midpoint. It should move about a quarter inch and then snap back into the groove. If it pulls away more than a quarter inch, it is too loose. If it barely moves at all, it is too tight. This is the correct tension for safe cutting.

Do I need to replace the sprocket when I replace the chain?

Not usually. A sprocket lasts through several chains if you keep the chain sharp and properly tensioned. Replace the sprocket only if the teeth are visibly flat, rounded, or chipped. A worn sprocket will cause a new chain to loosen quickly, so if that happens, have the sprocket inspected.