Remove the Old Chain

Start by unplugging the spark plug wire or turning off the fuel valve — you need the engine completely dead before you touch the chain. Let the saw cool for at least five minutes if you have just used it. Locate the side cover on the right side of the saw (the side facing you when you hold it normally). This cover is held on by one or two nuts, usually a quarter-inch or three-eighths-inch size. Use a socket wrench or adjustable wrench to turn these counterclockwise and remove them completely.

Once the cover is off, you will see the sprocket (the small gear the chain wraps around) and the chain itself. The chain is held in place by tension, not by bolts. Loosen the tension by turning the adjustment screw — on most Husqvarna models, this is a flathead screw on the side cover or near the sprocket. Turn it counterclockwise two or three full rotations. The chain should now hang loose enough that you can lift it off the sprocket by hand. Slide the chain off the sprocket and the guide bar, working slowly so it does not snag. Set the old chain aside.

Key Takeaways

  • Always disconnect the spark plug wire before removing the chain to prevent accidental starting.
  • The side cover comes off with one or two nuts; loosen the tension screw before trying to lift the chain away.
  • New Husqvarna chains come in different gauges and pitch sizes that must match your saw's specifications, printed on the guide bar or in your manual.
  • Proper chain tension means the chain sits snug against the bar but can be pulled away from the bar by hand at the midpoint.
  • The entire job takes 10 to 15 minutes once you have the correct replacement chain.

Check Your Chain Size Against the Guide Bar

Before you install anything, you need to confirm the new chain matches your saw. Look at the guide bar — the long metal piece the chain wraps around. Husqvarna prints the chain specifications directly on the bar, usually stamped into the metal near the tip. You are looking for two numbers: the pitch (usually .325 inch or .404 inch) and the gauge (usually .050 inch or .063 inch). Write these down or take a photo.

The pitch is the distance between the rivets that hold the chain links together. The gauge is the thickness of the drive links — the teeth that sit in the groove on the guide bar. If you buy a chain with the wrong pitch or gauge, it will not fit the bar or the sprocket, and you will have wasted money. Check your Husqvarna manual or the bar itself before you open the new chain box. If the numbers are not visible on the bar, your manual will list them by model number.

Install the New Chain on the Guide Bar

Lay the new chain on a clean surface and inspect it for any damage or missing links — chains sometimes arrive with a bent tooth or a cracked link. If it looks good, position the guide bar so the tip points away from you. Start threading the chain onto the bar at the tip, working the drive links (the teeth pointing down) into the groove that runs along the bar. The chain should slide smoothly; if it binds or resists, stop and check that the pitch and gauge are correct.

Continue wrapping the chain around the bar and over the sprocket. The sprocket sits at the base of the bar, closest to the engine. Make sure the chain teeth point forward on the top side of the bar — this is the cutting edge. On the bottom side of the bar, the teeth should point backward. If the teeth are reversed, you have threaded the chain backward and need to start over. Once the chain is fully seated on the bar and sprocket, replace the side cover and hand-tighten the nuts. Do not fully tighten yet.

Adjust the Chain Tension

Proper tension is critical — too loose and the chain will derail during use; too tight and you will burn out the sprocket and bar. The adjustment screw is the same one you loosened earlier. Turn it clockwise slowly while pulling the tip of the guide bar upward with your other hand. You are tightening the chain as you go. Stop when the chain sits snug against the bar but can still be pulled away from the bar by hand at the midpoint — about a quarter-inch of play is correct.

Once the tension feels right, fully tighten the side cover nuts with your wrench. Tighten them firmly but do not strip them by over-tightening — hand-tight plus a quarter turn is usually enough. Reconnect the spark plug wire. Run the saw for 30 seconds at idle, then let it cool and check the tension again. New chains stretch slightly during the first few minutes of use, so you may need to tighten the adjustment screw one more half-turn after that first run.

Common Mistakes to Avoid

The most frequent error is installing the chain backward. The teeth on the top of the bar must point forward in the direction the bar moves. If you cut with the chain running backward, you will not cut at all and you will damage the chain. Take two seconds to verify this before you start the engine.

The second mistake is over-tightening the chain. A chain that is too tight will not spin freely, will heat up rapidly, and will wear out the sprocket and bar in a few hours. If you cannot pull the chain away from the bar at all, it is too tight. Loosen the adjustment screw a half-turn and try again. The third mistake is forgetting to reconnect the spark plug wire after you finish. You will not damage anything, but the saw will not start, and you will spend 10 minutes troubleshooting before you realize what happened.

When to Replace the Guide Bar and Sprocket

If the guide bar is visibly bent, cracked, or has a groove worn deeper on one side than the other, replace it at the same time as the chain. A worn or bent bar will cause a new chain to wear out in a few hours. The sprocket is harder to inspect without removing it, but if your chain keeps derailing or stretching unevenly, the sprocket teeth may be worn flat. Husqvarna sprockets are inexpensive — usually $15 to $30 — and replacing it while you have the cover off takes only a few extra minutes.

To remove the sprocket, you will need a socket that fits the center nut holding it in place. This nut is usually a half-inch or nine-sixteenths-inch. Turn it counterclockwise to remove it, then slide the sprocket off the shaft. Slide the new sprocket on, replace the nut, and tighten it firmly. The sprocket should not wobble or move side to side. Then install the chain as described above.

Frequently Asked Questions

How often should I replace the chain on my Husqvarna?

This depends on how often you use the saw and what you cut. A chain used weekly on softwood may last 20 to 30 hours of cutting. A chain used occasionally on hardwood might last 10 hours. When the chain stops cutting efficiently and you have to push hard to make it bite, it is time to sharpen it. After sharpening two or three times, the teeth become too short and the chain must be replaced.

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

Yes, as long as the pitch and gauge match exactly. Brands like Oregon and Stihl make chains that fit Husqvarna saws. Check the specifications on your guide bar and buy a chain with the same numbers. The quality and price vary by brand, but any chain with the correct pitch and gauge will work.

What does it mean if the chain keeps coming off the bar?

The chain is too loose. Tighten the adjustment screw clockwise while pulling the bar tip upward. If tightening does not fix it, the sprocket or bar may be worn or bent. Inspect both for damage. If the bar is bent, replace it. If the sprocket teeth are flattened, replace the sprocket.

Do I need to drain the fuel before replacing the chain?

No. You only need to disconnect the spark plug wire and let the engine cool. The fuel stays in the tank. However, if you are working on the saw for more than 30 minutes, it is a good idea to turn off the fuel valve to prevent gas from leaking out of the carburetor.

How tight should the side cover nuts be?

Tight enough that the cover does not move, but not so tight that you strip the threads. Hand-tight plus a quarter turn with a wrench is the standard. If you over-tighten, you risk cracking the plastic cover or stripping the bolt holes. You should be able to remove them again with moderate hand pressure on the wrench.