Chainsaw Maintenance for Firewood Season

A chainsaw is the least forgiving machine most homeowners own. A mower slightly out of tune just cuts a little worse. A chainsaw out of tune cuts slower, kicks harder, eats a bar in a season, and has you leaning into a running saw to make it work. That last part is where people get hurt.

The good news: almost everything a chainsaw needs is quick and doable at the workbench. Here’s the order we work through a saw before firewood season.

1. The Chain Does the Cutting — Everything Else Just Helps

A sharp chain pulls itself into the wood — you guide it, you don’t push it. Read what comes out of the cut: square chips mean sharp, fine powder means dull, and a cut that curves means the teeth on one side are longer than the other.

How often depends on what you’re cutting. Clean hardwood might give several tanks between touch-ups. One brush against dirt, a fence staple in a hedgerow tree, or a nail in reclaimed lumber takes a chain from sharp to useless in one second.

Two things people miss filing at home. All the teeth must end up the same length — file everything back to match the shortest damaged tooth, or the saw cuts crooked no matter how sharp it feels. And depth gauges (rakers) need lowering as teeth get shorter, because the raker controls how big a bite each tooth takes. Never touch them and the chain eventually rides on the gauges and stops cutting — the most common “my new chain is already bad” call we get. A shop grind resets every tooth and gives you a reference to file back to, same logic as mower blade sharpening.

2. The Bar Is a Wear Part, Not a Permanent Fixture

Bars wear, and a worn bar chews through good chains. Take the chain off and check four things:

• Rail wear. The rails should be square and even. Knock burrs down with a flat file. Splayed or uneven rails make the chain lean, and the saw cuts in an arc.
• The groove. Scrape it out — it packs solid with sawdust and bar oil, which blocks oil and traps grit against the drive links.
• The oil hole. The small hole at the base of the bar feeds oil into the groove. Ten seconds to clean, and it prevents expensive damage.
• The sprocket nose. If your bar has one, it should spin freely without wobble. Grease it if there’s a port.

Flip the bar every time you replace the chain — most cutting happens on the bottom edge, so flipping roughly doubles bar life. Check the drive sprocket while the chain is off; grooved or hooked teeth ruin new chains.

3. Confirm the Oiler Actually Works

Bar oil is not optional, and used motor oil is not a substitute — it carries metal particles, thins at working temperature, and lacks the tackiness that keeps oil on a chain moving at speed.

Test it before you cut: hold the bar tip a few inches above clean cardboard and run the throttle up briefly. You want a distinct line of oil thrown off the tip. Nothing there means a plugged port, a clogged bar hole, an empty tank, or a failed pump — and a dry bar blues the rails and destroys a chain in one afternoon.

4. Fuel: Mix It Right, Mix It Fresh

Two-stroke saws get their lubrication from the oil in the fuel. Get the mix wrong and the engine either runs lean and seizes or runs rich and carbons up. Neither is cheap.

• Use the ratio your saw calls for. Most modern saws are 50:1; some older units are 40:1. It’s on the fuel cap or in the manual. Don’t split the difference between two saws — keep separate cans.
• Measure it, and mix small. Pre-measured oil bottles exist because eyeballing goes badly, and mixed fuel has a short shelf life.
• Mind the ethanol. E10 pulls moisture out of the air and attacks the rubber and plastic in small-engine fuel systems — the biggest cause of the carburetor work we see. Full detail in ethanol gas and small engines.

If the saw sat all summer on old mix, don’t just top it off and yank the rope. Drain it, put fresh mix in, and expect carburetor cleaning if the old fuel varnished up.

5. Air Filter, Spark Plug, and Cooling Fins

A chainsaw lives in a cloud of its own sawdust and plugs up faster than anything else in the shed.

• Air filter. Check it every few tanks during heavy cutting — a choked filter runs the engine rich, fouls plugs, and costs power. Some are washable, some tap-it-out only.
• Spark plug. Light brown is right; black and sooty means rich or a plugged filter; wet means flooded. Gap it to spec and replace it if the electrode is rounded over.
• Cooling fins and starter screen. Both pack with sawdust and pitch. Blocked airflow overheats the engine, and heat is what kills two-strokes.

6. The Safety Gear Is Part of the Maintenance

The section people skip, and the one that matters. Each of these is designed to work exactly once, on the worst day:

• Chain brake. Saw off, push the front hand guard forward — the chain should lock solid, then move freely when you pull it back. A brake gummed with pitch won’t catch during kickback.
• Throttle lockout. The trigger should not move at all unless the lockout lever is depressed.
• Chain catcher. The small pin under the bar catches a chain that breaks or derails. Missing or cracked off, replace it.
• Anti-vibration mounts. Cracked rubber mounts make the saw harder to control and more tiring to run.
• Chain tension. Correctly tensioned, the chain pulls a short way off the bottom of the bar, snaps back, and still turns by hand. Re-check after the first few cuts — a new chain stretches as it warms.

7. Put It Away Right in the Spring

Most fall no-start calls were created the previous spring. When the saw goes back in the shed, drain the fuel or run it dry, clean the pitch off bar and chain, and store it dry with the bar covered — same logic as winterizing your ATV or mower.

When to Call the Shop

Filing a chain and cleaning a filter are homeowner jobs. A saw that won’t hold a tune, dies under load, leaks fuel, has lost compression, needs carburetor work, or has a chain brake that won’t lock is bench work — and a chainsaw is not the machine to experiment on.

Turf & Trail Small Engine Repair is based in Richmond, KY and serves Berea, Waco, Kirksville, and the rest of Madison County. We sharpen chains, replace bars and sprockets, rebuild carburetors, and diagnose no-starts on every major brand, with pickup and delivery available. You’ll get a firm quote before any work begins — no surprise bills.

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Chainsaw Maintenance FAQ

How often should I sharpen my chainsaw chain?
Any time the saw starts throwing fine sawdust instead of chips, pulls to one side, or needs you to push it through the cut. In clean wood that might be every few tanks of fuel. One touch of dirt, a hidden nail, or a fence staple can dull a chain in seconds.

What fuel mix does a chainsaw use?
Whatever ratio the manufacturer calls for — commonly 50:1 on modern saws and 40:1 on some older ones. Check the fuel cap or the manual, measure it rather than eyeballing it, and mix it fresh in small batches.

Why isn’t my chainsaw oiling the bar?
Usually a plugged oil hole in the bar, sawdust packed into the bar groove or oiler port, an empty tank or the wrong oil viscosity, or a worn oil pump. Never keep cutting once you suspect the oiler has quit — it ruins bars and chains fast.

Do you sharpen chains and repair chainsaws in Richmond, KY?
Yes. We sharpen chains and service chainsaws at the shop in Richmond and across Madison County, KY, and you get a firm quote before any work begins. Call (859) 661-8877.