Learn How to Start a Stihl Chainsaw

Understanding Your Stihl Chainsaw's Basic Components Before Starting

Before you pull the starter cord on a Stihl chainsaw, it's worth knowing what you're actually working with. Stihl manufactures over 30 different chainsaw models for homeowners and professionals, ranging from small 25cc engines for light trimming to large 79cc saws for serious forestry work. Each model has the same fundamental parts, though their locations might vary slightly depending on the specific saw you own.

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The engine on a Stihl chainsaw is a two-stroke design, which is significantly different from your car's four-stroke engine. This matters because a two-stroke engine requires fuel mixed with oil—you don't add oil separately to a reservoir like you would in a truck. The typical fuel-to-oil ratio for Stihl chainsaws is 50:1, meaning 50 parts gasoline to 1 part Stihl two-stroke engine oil. Getting this wrong is one of the most common reasons chainsaws won't start or run poorly.

You'll notice several key controls on the saw itself: the on/off switch, the choke lever (sometimes called the cold start lever), the throttle trigger, and the primer bulb on some models. The air filter housing sits on top of the engine, and underneath you'll find the spark plug. Understanding where these components are located takes the mystery out of the starting process and helps you troubleshoot if something goes wrong.

The fuel tank capacity on most Stihl homeowner models ranges from 0.3 to 0.6 liters (about 10 to 20 ounces). This might seem small, but it's intentional—two-stroke engines are fuel-efficient, and homeowners typically don't need extended run times. Larger professional models hold more fuel but operate on the same starting principles.

Takeaway: Locate the fuel tank, choke lever, on/off switch, and primer bulb on your specific model before attempting to start. Consult your owner's manual (usually available on Stihl's website if you don't have the physical copy) to confirm these locations and your fuel-to-oil ratio.

Preparing the Correct Fuel Mixture for First-Time Use

The fuel mixture is non-negotiable when it comes to starting a Stihl chainsaw. Most new users make mistakes here, which leads to starting difficulties or engine damage. Unlike lawnmowers or other equipment that might tolerate plain gasoline, Stihl two-stroke engines absolutely require oil in the fuel to lubricate the moving parts inside the engine.

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To mix fuel properly, you'll need fresh unleaded gasoline (91 octane or higher) and Stihl two-stroke engine oil. Stihl sells its own branded oil, but other two-stroke oils meeting ISO EGD or JASO FD specifications work too. Never use car oil, boat oil, or any other type of oil—these don't blend properly with gasoline and will damage the engine.

The math for a 50:1 ratio works like this: if you're mixing 2 liters of gasoline, you need 40 milliliters (about 2.7 tablespoons) of oil. Most people find it easier to use pre-measured containers. Pour the oil into a clean fuel can first, then add the gasoline. Shake or stir thoroughly for at least two minutes—the mixture should look uniform and smell pungent. Don't skip this step; incomplete mixing means some parts of the engine get too much oil and others get too little, both problematic.

One detail many owners overlook: fuel degrades over time. Gasoline sitting in a tank for more than 30 days can break down, forming varnish that clogs the carburetor and fuel lines. If your chainsaw has been stored for more than a month, drain the old fuel and start fresh. This is the culprit behind most "won't start" problems on chainsaws that have been sitting idle.

Takeaway: Mix fuel in a separate container before pouring it into the chainsaw's tank. Use only fresh gasoline mixed with Stihl-branded or equivalent two-stroke oil at a 50:1 ratio. If the saw hasn't been used in over a month, drain old fuel and mix a fresh batch.

The Cold Start Procedure: Step-by-Step from Stop to Running

Starting a cold Stihl chainsaw—one that hasn't been run recently or at all—follows a specific sequence. This is different from restarting a warm saw, so pay attention to which situation applies to you. Most starting problems occur because people skip steps or perform them out of order.

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For a cold start, begin by placing the chainsaw on flat ground. Engage the chain brake by pushing the top handle guard forward; this prevents the chain from moving when the engine fires up. Set the on/off switch to the "on" position. Now move the choke lever to the full choke position (marked with a closed door symbol on most models). The choke restricts airflow to the engine, making the fuel mixture richer—essential for starting when the engine is cold.

If your Stihl model has a primer bulb (a small rubber ball on the side of the engine), press it 6 to 10 times until you see fuel in the clear line. This pre-fills the carburetor with fuel, reducing the number of pulls needed. Place your right foot through the rear handle so the chainsaw is steady against your leg. Grip the front handle with your left hand and pull the starter cord with your right hand using a firm, steady motion—not a slow drag. Most models require 2 to 8 pulls before the engine catches.

Once the engine fires, it will run at a high idle because the choke is still engaged. Let it run for 3 to 5 seconds, then move the choke lever to the half-choke position (the symbol usually shows a partially open door). After another few seconds, move it fully open. If the engine stalls, return to full choke and repeat the process—don't just keep pulling the cord.

Takeaway: Cold starts require: chain brake engaged, switch on, full choke, primer bulb primed (if equipped), firm starter cord pulls, then gradual choke reduction as the engine warms. This sequence matters more than how hard you pull.

The Warm Start Procedure and Preventing Unnecessary Pulls

After your Stihl chainsaw has been running and you stop it—perhaps to refuel, change bars, or take a break—restarting is different and faster. A warm engine still has residual heat and fuel in the carburetor, so it doesn't need the same enriched mixture that a cold engine requires. Understanding this distinction saves frustration and reduces wear on the starter cord.

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For a warm restart, engage the chain brake again and set the switch to "on." This time, move the choke lever all the way open—no choke enrichment needed because the engine is warm. Do not use the primer bulb if your model has one; the carburetor is already full of fuel. Simply pull the starter cord once or twice with a smooth motion. The engine should fire within one to three pulls. If it doesn't, move the choke to half-choke and try again.

One common mistake: people keep pulling the starter cord endlessly on a warm restart when the engine doesn't immediately start. After three pulls with the choke fully open, stop. Check whether the switch is actually in the "on" position—you'd be surprised how often it's been bumped to "off." Verify the chain brake isn't sticking. If these are fine, move the choke to half-choke for two more pulls. Usually, this sequence resolves the problem.

The warm-start distinction also applies if you're stopping the saw for a few minutes and restarting—say, moving from one tree to another. The engine cools quickly (within 10 to 15 minutes it's considered cold), but if you're working continuously, you'll be doing warm restarts. Warm restarts feel easier than cold starts, which can actually create a false sense that something's wrong when cold starting feels "harder." It's normal.

Takeaway: Warm restarts use a fully open choke, no primer bulb, and very few starter cord pulls. If the