Chainsaw Repair and Maintenance
My sons think I try to use a chainsaw on every project, and I admit it gets used a lot on our jobs. It may be because of my years spent logging in the Oregon rain forests. Of course, it could also be a reaction to all the years I’ve spent making precise cuts doing trim work, so the half-inch-is-close-enough mode of chainsaw work is appealing.
To me, big wood calls for a chainsaw. Fence posts, deck frames, house beams, wood sheds, boat docks, axle blocks, heavy pruning, brush clearing, trail building and firewood are often made quicker and easier with a chainsaw.
Even if you show restraint and get out your chainsaw only occasionally, you still want it to run when you pull the starter cord. Proper maintenance greatly increases your odds. Additionally, your saw will be safer to operate and last for many years if it’s properly maintained.
Chainsaw maintenance comes down to a few basic concepts: clean, inspect, replace, adjust and lubricate.
As you go through your maintenance checklist, inspect the operating components of the saw. Always keep an eye out for worn, broken or missing parts. Pay particular attention to safety features such as the throttle trigger, shut-off switch and chain brake.
To clean the saw I use the saw’s multi-tool (screwdriver/wrench) to remove the bulk of sawdust, and then hit it with some compressed air. You can use soap and water as well. Either way, you’ll need to do some additional cleaning when you start removing parts, because sawdust combined with pitch and bar oil tends to get packed into tight spaces.
Remove the top cover of the engine housing to expose the carburetor and the top of the cylinder head. This gives you access to both the air filter and spark plug. Remove the air filter, clean it (or replace it) and re-install it. You can use compressed air or soap and water to clean most filters, but make sure the filter is thoroughly dry before re-installing.
Remove the spark plug and inspect it. Replace it or clean off oil buildup and carbon deposits, set the gap and re-install.
Note the direction of the lettering on the bar. Are the words and logos upright or upside-down? Remove the clutch cover, chain and bar. Clean everything in this area paying particular attention to the chain oil ports and the chain brake.
Thoroughly inspect the bar for bends, nicks or burrs. Clean the chain groove and re-install the bar turned 180 degrees from the most recent orientation. For most bar designs, periodically flipping the bar helps promote even wear.
Inspect the chain for damage and replace or re-install. Install the clutch cover/brake/chain adjustment assembly and adjust the chain tension. Sharpen the chain and file the depth gauges.
The engine oil for a two-stroke goes right into the cylinder with the fuel. Remember to add two-stroke oil to your gas at the proper ratios, and stress this point to anyone who borrows your saw.
Chain lubrication is also very important. Chainsaws are designed with automatic oilers, which have reservoirs that should be filled each time you fill the saw’s gas tank. Pay attention to the chain to make sure it is getting oiled during use.
As with your truck, major service items come up less often than those we’ve mentioned. Major service items include checking the fuel filter, cleaning the carburetor, and flushing out the fuel and oil tanks.
Be sure to drain the gas tank and let the engine consume any residual fuel before storing your saw for the season. Take care of your tools, and they’ll take care of you.
Most chainsaw maintenance can be done with the saw’s multi-tool, files, an air hose and a rag.
Remove the top cover of the engine housing to expose the carburetor and the top of the cylinder head. This gives access to the air filter and spark plug. Clean the air filter and carefully inspect it for damage.
If you are not familiar with how the electrode and ground should look, compare the spark plug with the new spare.
If the electrode is damaged, install a new or cleaned spark plug.
Loosen (but do not remove) the nuts that hold the rear sprocket/chain brake assembly in place.
Turn the chain tension adjustment screw to create slack in the chain. This takes a little tension off the adjustment pin to allow for removal of the cover.
Remove the cover, which on the Husqvarna includes the chain brake assembly. Note the buildup of sawdust and oil.
Slide the bar back toward the engine to create maximum slack in the chain. To remove, first take the chain off the front of the bar. Then carefully take it off the drive sprocket and work it around the clutch assembly.
With the chain set aside, remove the bar, again noting its orientation (up or down).
Use a stick or screwdriver to scrape the sawdust and oil buildup out of the area near the clutch and sprocket assembly.
Use an air hose and nozzle to blast out the remainder of the sawdust. As you clean these usually dirty areas of the saw, watch for worn, cracked or bent parts like this chain guard, which obviously took a hit from a thrown chain.
Clean and inspect the bar. Watch for any bends or nicks in the metal.
Make sure there are no burrs or obstructions in the bar groove.
With everything cleaned, it’s much easier to see potential problems.
Put the chain around the sprocket, then put the bar in place. Now you can start aligning the chain with the bar groove.
With the chain riding in the bar, extend the bar away from the engine to pick up the slack in the chain. Now you’re ready to line the tension pin with the hole in the bar.
Pay attention to how the parts line up as you put the cover back on. The brake band needs to fit around the clutch, and the tension pin should be pointing at the opening in the bar.
With the clutch cover back in place, apply the nuts “finger tight” to allow the bar to slide for chain adjustment. Adjust the chain so the guides are just inside the bar, but no tighter.
It may help to support the saw at the bar tip during chain adjustment to find the best tension location.
This tooth sustained some damage from a rock. It needs to be filed back until the top surface is consistently flat.
There are two important angles for sharpening a chain. First is the angle to the flat side of the bar and the other is the angle to the top of the bar.
Maintain some upward pressure as needed to make sure you have only a slight hook in the vertical cutting edge on the outside of the tooth.
A file gauge can help you get the angle you need to the flat direction of the saw bar.
A depth gauge helps determine the right height for the “rakers.” These little points on the chain between saw teeth keep the individual teeth from diving too deep into the wood. However, left at full height they prevent the teeth from cutting deep enough after a couple of sharpenings.
Use a flat file across the top of the depth gauge until the “raker” point is flush with the flat point on the gauge.
Make a couple of test cuts on a piece of fire wood. Cut thin slices so you can see if the cuts run parallel.
The saw should produce some nice shavings and not just fine dust.
Hold a straight edge across the cut surface. A noticeable convex or concave curve over the width of the cut indicates that the teeth on one side of the bar are cutting more aggressively than the other.
A well maintained chainsaw should provide years of safe service.
Like most gas powered machines, keeping a chainsaw lubricated is a top priority. The two-stroke engine does not have an automatic oil injector, so the engine lube oil must be added to the gas.
Pre-measured amounts of two-stroke oil help get the ratios correct for mixing small amounts of chainsaw gas. Make sure you put the correct number of gallons in the gas can for the amount of oil used.
Fill the bar oil tank every time you fill the fuel tank. This is the lubrication for chain’s link-to-link connections and for the contact points where the chain touches the bar.
You can make sure the oiler is working by holding the throttle open and pointing the saw at a clean piece of wood. The saw should shoot a perceptible streak of oil onto the wood.