There's nothing more frustrating than gearing up for a day of cutting, getting the PPE on, and pulling the starter cord only to hear... silence. Or a sputter, a cough, and then silence.
If you're standing in the paddock staring at a silent saw right now, you're not alone — it happens to everyone eventually. The good news: you probably don't need a mechanic. Nine times out of ten, a chainsaw that won't start comes down to one of three simple causes. Work through them in order before you throw it in the ute.
A quick safety note before you touch anything: you'll be handling fuel and working around the ignition system, so do this outdoors, away from any ignition source, with the chain brake on and eye protection handy. If anything below is outside your comfort zone, your servicing dealer does this every day.
Reason 1: Stale Fuel — Why a Chainsaw Won't Start After Sitting
If the saw has been in the shed since last winter with fuel in the tank, this is almost certainly your problem.
Modern unleaded petrol has a shelf life. Within a matter of weeks it starts to degrade — the volatile vapours that ignite easily evaporate off, leaving behind a gummy residue that clogs the works.
The Australian factor: a lot of our pump fuel is E10, and ethanol loves water. Leave the saw sitting for a month and the ethanol absorbs moisture from the air. That watery sludge sinks to the bottom of the tank — exactly where the fuel pickup sits. Your saw is trying to run on water and gum.
The fix:
- Don't just top it up. Fresh fuel poured onto bad fuel doesn't fix bad fuel.
- Drain the tank completely into a safe, sealed container (your local transfer station takes old fuel).
- Mix a fresh batch of two-stroke using 95 or 98 octane premium. Skip the E10 for small engines if you can.
- Prime and pull. It may take a few extra pulls to draw the fresh mix through the lines, but it'll usually come to life once the old fuel is cleared.
Reason 2: A Flooded Engine — When It Has Spark and Fuel but Won't Start
This is the most common user error going, and it catches pros and beginners alike.
A cold saw needs the choke on to start. But pull the cord too many times with the choke on and you dump too much fuel into the engine — the spark plug gets wet and can't fire.
How to tell it's flooded:
- You can smell raw petrol.
- It nearly started (a "pop"), but you kept pulling on full choke.
- The cord suddenly feels much harder to pull than usual. Stop pulling immediately — that can be hydro-lock, and forcing it can damage the engine.
The fix: the safest, most reliable way to clear a flood is to physically let the excess fuel out rather than trying to burn it off with the throttle held open. You'll need your scrench.
- Remove the spark plug. Pop the top cover and unscrew the plug.
- Dry the plug. If it's wet with petrol, wipe it clean with a rag.
- Clear the chamber. With the plug out, turn the saw so the plug hole faces the ground and pull the cord 6–10 times. You'll see a fine mist of fuel leave the hole — that's the flood clearing.
- Reassemble and start. Plug back in, cover on, and set the saw to fast idle / warm start (on most saws: engage the choke, then click it straight off). Don't use full choke. It should fire within a couple of pulls.
Reason 3: A Clogged Air Filter — The Aussie Hardwood Dust Problem
An engine needs three things to run: fuel, spark, and air. If you cut Australian hardwoods like Red Gum or Ironbark, the air side has a uniquely local enemy.
Pine sawdust is chunky. Dry Aussie hardwood throws off a fine, talc-like dust that coats everything — and if it cakes the air filter, the engine suffocates. It can't pull enough air, so it pulls extra fuel instead and floods itself (see Reason 2 — the two problems travel together).
The fix:
- Pop the top cover. Most saws have a clip or single screw over the filter.
- Inspect the filter. If it looks like a fuzzy felt pad or is caked in grey dust, it's blocked.
- Clean it — tap it gently against a hard surface, or use a soft brush or compressed air blown from the inside out.
- Check the spark plug while you're in there. Black and oily means clean it with a wire brush — or just replace it, they're cheap.
And while the cover's off: hardwood dust that kills air filters is the same stuff that packs into your bar groove and chain. If the chain's looking tired too, our Search by Chainsaw tool will tell you the exact replacement loop for your model.
Won't Start After Refuelling on a Hot Day? Vapour Lock
A special case for Australian summers. If the saw starts fine cold but refuses to restart after you stop and refuel on a 30°C+ day, you may have vapour lock — the fuel is literally vaporising in the lines before it reaches the engine. It affects every brand, Stihl and Husqvarna included.
The fix is patience, not pulling: crack the fuel cap to release the pressure, give the saw a few minutes in the shade to cool, then restart. Topping up with cooler fuel from an insulated container helps too.
Still Won't Start?
If you've got fresh premium fuel, you've cleared the flood, and the air filter is clean, the next suspects further down the line are a blocked fuel filter (it lives inside the tank on the end of the pickup line), a fouled or dead spark plug, or a carburettor gummed up by old fuel.
Beyond that, you're into genuine shop territory: ignition module faults, carburettor rebuilds, or compression loss. There's no shame in it — a servicing dealer can diagnose in minutes what costs a weekend of guesswork in the shed.
Chainsaw Starting Questions, Answered
Why won't my chainsaw start after sitting for months?
Almost always stale fuel. Petrol starts degrading within weeks, and E10's ethanol absorbs moisture while the saw sits. Drain it, mix fresh premium two-stroke, and try again — see Reason 1.
My chainsaw has spark and fuel but won't start. Why?
If spark and fuel are confirmed, the usual suspects are a flooded engine (Reason 2), a blocked air filter (Reason 3), or a fault further along the fuel path — a clogged fuel filter or a carburettor gummed by stale fuel.
Why won't my Stihl start after refuelling on a hot day?
Likely vapour lock — fuel vaporising in the lines in the heat. It's not a Stihl problem specifically; it affects all brands. Crack the fuel cap, let it cool a few minutes, and restart.
How many pulls should it take to start a chainsaw?
A healthy saw on a cold start typically fires within a handful of pulls on choke, then starts promptly once the choke's off. If you're ten-plus pulls in, stop — you're probably flooding it, and more pulling makes it worse.
Is it bad to keep pulling the cord if it won't start?
Yes. Repeated pulling on full choke floods the engine — and if the cord suddenly feels much harder to pull, stop immediately. That can be hydro-lock, and forcing it risks real engine damage.
Beaten all three fixes and it still won't fire? Post the symptoms on the Alpine Chain Co. Community Forum — between the lot of us, someone's fought the same saw before.