How to Start a Gas Chainsaw: A Step-by-Step Starting Guide
How to start a gas chainsaw safely from a cold or warm engine, including choke positions, starting stance, flooded engine recovery and safety gear checks.
By FirewoodGearHQ Editorial
Updated October 9, 2026
To know how to start a gas chainsaw, place the saw flat on clear ground, push the front hand guard forward to lock the chain brake, and switch the ignition on. Set the choke to the cold start position, prime the purge bulb if your saw has one, place your boot inside the rear handle, and pull the starter cord until the engine pops. Finally, open the choke to the fast-idle position, pull the cord again until the engine runs, and tap the throttle trigger to return the saw to normal idle.
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The quick answer
Starting a gas-powered saw is straightforward on a 2-cycle engine once you know the sequence. A cold engine needs fuel enrichment from the choke and purge bulb if equipped. When the fuel ignites and pops, opening the choke provides air for continuous running. Keeping the saw flat on clear ground with the chain brake locked ensures steady control.
Whether selecting a saw from our chainsaws hub or cutting firewood with the best chainsaw for firewood, avoid rushing. Rushing causes flooding when unburned fuel coats the spark plug. Our gas chainsaws guide explains how engine displacement affects starting effort.
Chainsaw starting specifications by model
Starting resistance depends on engine displacement and starting assist mechanisms. Stated displacement figures and starting features from manufacturer listings include:
| Chainsaw model | Displacement or power | Starting features and notes |
|---|---|---|
| Troy-Bilt TB4216 | 42cc engine | SpringAssist pull handle, 2-cycle engine, 16-inch bar |
| PRORUN PCS560C | 55.5cc engine | Spring-assisted pull handle, decompression valve, 2-cycle engine, 20-inch bar |
| Echo CS-590-20AA | 59.8 cc engine | High displacement engine, 20-inch bar |
| Stihl MS 170 | 30 cm³ displacement (1200 W) | Compact displacement, 30 cm guide bar |
These specifications show why starting stance matters. The 42cc Troy-Bilt TB4216 uses spring-assisted starting to smooth pull resistance. The 55.5cc PRORUN PCS560C provides a decompression valve to vent cylinder pressure. Saws like the 59.8 cc Echo CS-590-20AA require a firm stance to pull against higher compression, while the 30 cm³ Stihl MS 170 with a 30 cm guide bar has a compact 1200 W rating with lighter recoil resistance. See the best small gas powered chainsaw for compact options, or check the best heavy duty gas chainsaw for timber saws.
How to start a gas chainsaw step by step
Starting a cold saw requires following a precise sequence so the carburetor delivers the correct air-fuel mixture without flooding the combustion chamber. Follow these steps every time you fire up a cold saw:
Engage the chain brake
Push the front hand guard forward toward the guide bar until it clicks into place. This locks the brake band around the clutch drum, preventing chain rotation if the engine fires at high throttle. Never start a saw without the chain brake engaged.
Set the choke and prime the fuel system
Set the ignition switch to on. If equipped with a flexible purge bulb, press it repeatedly until fuel fills the bulb and clears air from the carburetor. Next, move the choke lever to full choke, which restricts airflow to draw fuel into the cold cylinder.
Place the saw flat on clear ground
Place the saw flat on level, clear ground with the bar touching nothing. Place your right boot toe through the rear handle opening to hold the saw body down firmly. Grasp the front handlebar with your left hand, locking your elbow straight to resist sudden movement.
Pull the starter cord to pop the engine
Grip the starter handle with your right hand. Pull slowly until the starter pawls engage, then pull upward briskly and smoothly. Repeat until the engine fires with a brief pop or sputter, confirming ignition. Stop pulling immediately once it pops to avoid flooding.
Open the choke and start the engine
Move the choke to the half-choke or fast-idle setting, opening the choke plate while holding the throttle latch open. Pull the starter cord again until the engine runs. Tap the throttle trigger immediately to release fast idle and let the saw idle smoothly before cutting.
How to start a warm gas chainsaw
A warm engine retains operating heat, allowing fuel to vaporize without full choke enrichment. Starting a warm saw requires leaving the choke open to prevent flooding.
Place the saw on clear ground and push the front hand guard forward to lock the chain brake. Turn the ignition switch on, leaving the choke open. Secure the saw with your boot in the rear handle, hold the front handlebar, and pull the starter cord until it fires. Disengage the chain brake before throttling up to cut.
What happens if the engine floods
Flooding occurs when pulling the starter cord with the choke closed draws excess fuel that wets the spark plug electrode, preventing ignition. If you smell raw gasoline after multiple pulls, the cylinder is flooded.
To clear a flooded engine without disassembly, set the choke completely off to the open run position. With the chain brake engaged, pull the starter cord repeatedly on clear ground. The incoming air clears excess fuel until the engine fires. Once running, tap the throttle trigger to return to idle.
If flooding persists, remove the spark plug with a scrench and wipe the electrode dry. With the ignition switched off and plug removed, pull the starter rope several times to expel liquid fuel. Reinstall the spark plug firmly, reconnect the wire boot, and start with the choke off.
Essential safety gear and work area setup
Always wear cut-retardant chainsaw chaps to protect your legs, along with a forestry helmet featuring a mesh face screen and hearing protection against 2-cycle engine noise. Sturdy leather gloves and cut-resistant steel-toe boots complete personal protection.
Beware of rotational kickback, which happens when the chain around the upper nose of the guide bar strikes debris and kicks upward. Keeping the chain brake locked during startup stops accidental chain movement. Clear the work zone of tripping hazards, keep bystanders clear, and never cut alone. Leave tree felling to certified professional arborists. These precautions reflect guidelines from the OSHA logging safety program.
Wear cut-resistant chaps, a helmet with face screen and hearing protection, gloves and sturdy boots. Know where the kickback zone is (the upper tip of the bar), keep the chain brake working and the chain sharp, and never cut alone in the woods. Felling trees is hazardous work: hire a professional for large, leaning or storm-damaged trees, especially near buildings or power lines. See OSHA logging safety for chain saw operators. Read our Safety Disclaimer.
Frequently Asked Questions
Why does my gas chainsaw not start?
Common causes include an off ignition switch, stale fuel, a dirty filter, or engine flooding. Confirm the switch is on, ensure fresh fuel mix fills the tank, and avoid over-choking.
How do I know if my chainsaw engine is flooded?
A flooded saw smells strongly of raw gas and fails to fire. Removing the spark plug reveals a wet, dark electrode coated in fuel.
Should the chain brake be locked when starting?
Yes. Engaging the chain brake locks the chain so it cannot turn at starting idle, protecting your legs and hands from contact.
Can I start a gas chainsaw by drop starting it?
No. Drop starting while holding the saw mid-air is dangerous and prohibited by OSHA safety rules because you lose physical control of the bar and saw.
What fuel mix does a 2-cycle gas chainsaw need?
A 2-cycle saw requires gasoline blended with 2-cycle engine oil at the manufacturer’s specified ratio. Running unmixed gas causes rapid cylinder damage.
Why does the chain spin when the saw starts?
Starting on fast idle holds the throttle partly open. Without the chain brake locked, the centrifugal clutch spins the chain immediately upon starting.
Related guides
See the chainsaws hub, the gas chainsaws guide and the chainsaw gear guide for equipment overviews. When cutting firewood cords, compare our top picks in the best chainsaw for firewood and keep your cutters keen with the best chainsaw sharpener. If you need a saw for property cleanup, read our best 16-inch chainsaw and best small gas powered chainsaw comparisons, or check the best heavy duty gas chainsaw for felling and bucking heavy logs. Need replacement cutting hardware? Explore the best chainsaw chain, the best 16-inch chainsaw chain, the best 18-inch chainsaw chain, and the best chainsaw chain for hardwood. Also see our guide to what is a top handle chainsaw. Also see our guide on how to check if your chainsaw or log splitter is recalled.
About the author
The FirewoodGearHQ editorial team researches firewood and wood heating equipment from published specifications, ratings and warranty terms, and scores every pick the same way. We do not run our own product trials.