Stihl MS171 Chainsaw Tips (5 Pro Hacks for Smooth Starts)

I still remember the day I got my first chainsaw. It was a Stihl, much like the MS171 we’re going to talk about today, and I was so eager to start cutting firewood. But, like many beginners, my enthusiasm quickly turned to frustration when the darn thing wouldn’t start smoothly. Countless pulls, flooded engines, and a sore shoulder later, I realized there was more to it than just yanking a cord.

The Stihl MS171 is a popular choice for homeowners and light-duty users because it’s lightweight, reliable, and relatively affordable. However, even the best tools can be finicky. So, I’m going to share five pro hacks that will help you get smooth starts every time with your Stihl MS171 chainsaw. These tips are based on years of experience, countless cords of wood, and a few hard-earned lessons along the way. Let’s dive in!

Understanding the Stihl MS171: A Foundation for Smooth Starts

Before we get to the hacks, it’s essential to understand the basics of the Stihl MS171. This chainsaw, like most two-stroke engines, relies on a precise mix of fuel and air to ignite. Any deviation from this optimal mixture can lead to starting problems.

The Two-Stroke Engine Explained

The MS171 uses a two-stroke engine, which means it completes a power cycle in two strokes of the piston (one up and one down). Here’s a quick breakdown:

1. Intake/Compression: As the piston rises, it creates a vacuum in the crankcase. This draws in the fuel-air mixture through the carburetor.
2. Combustion/Exhaust: The spark plug ignites the compressed fuel-air mixture, forcing the piston down. As the piston moves down, it opens the exhaust port, allowing the burnt gases to escape.

Because the two-stroke engine lubricates the internal components with the fuel mixture, using the correct fuel-oil ratio is crucial.

Essential Components for Starting

• Fuel Tank: Holds the gasoline and two-stroke oil mixture.
• Fuel Line: Delivers fuel to the carburetor.
• Fuel Filter: Prevents debris from entering the fuel line.
• Carburetor: Mixes fuel and air in the correct proportions.
• Spark Plug: Ignites the fuel-air mixture.
• Ignition System: Provides the electrical spark to the spark plug.
• Choke: Restricts airflow to enrich the fuel mixture for cold starts.
• Primer Bulb: Purges air from the carburetor and primes the engine with fuel.

Pro Hack #1: The Fresh Fuel Formula

One of the most common reasons for hard starts is stale fuel. Gasoline degrades over time, especially when mixed with two-stroke oil. The lighter hydrocarbons evaporate, leaving behind a less volatile mixture that’s harder to ignite.

• The Problem: Stale fuel can cause a variety of issues, including hard starting, poor performance, and even engine damage.
• The Solution: Always use fresh fuel. I make it a rule to mix only the amount of fuel I’ll use within a month.
• Data Point: Studies show that gasoline can lose up to 50% of its octane rating in just three months.
• Actionable Advice:
  • Mix fuel in small batches.
  • Use a fuel stabilizer if you need to store fuel for more than a month.
  • Empty the fuel tank of your chainsaw if you won’t be using it for an extended period.
  • Use high-quality two-stroke oil. I prefer synthetic oils because they provide better lubrication and burn cleaner.
• Real-World Example: I once had a chainsaw that refused to start after sitting unused for six months. I drained the old fuel, replaced it with a fresh mixture, and it started on the second pull.
• Wood Science Insight: The presence of ethanol in gasoline can exacerbate fuel degradation. Ethanol absorbs water, which can lead to phase separation and corrosion of fuel system components.

Fuel-Oil Ratio: The Golden Rule

The Stihl MS171 typically requires a 50:1 fuel-oil ratio. This means 50 parts gasoline to 1 part two-stroke oil. Always consult your owner’s manual for the exact ratio recommended for your model.

• Why it Matters: Too much oil can cause excessive smoke and carbon buildup, while too little oil can lead to engine damage due to insufficient lubrication.
• Tip: I use a graduated mixing bottle to ensure accurate measurements. It’s a small investment that can save you a lot of headaches.

Pro Hack #2: Mastering the Starting Sequence

The starting sequence is crucial for getting your MS171 running smoothly. Here’s the step-by-step method I use:

1. Cold Start:
   • Engage the chain brake. This is a safety must.
   • Move the master control lever to the cold start position (usually fully down). This engages the choke.
   • Prime the carburetor by pressing the primer bulb several times until you see fuel flowing through the clear fuel line.
   • Place the chainsaw on a firm surface and hold it securely.
   • Pull the starter cord sharply until the engine attempts to start (it will sputter or briefly run).
   • Move the master control lever to the half-throttle position (usually one click up). This disengages the choke but keeps the throttle slightly open.
   • Pull the starter cord again until the engine starts and runs smoothly.
   • Allow the engine to warm up for a few seconds before disengaging the chain brake and using the chainsaw.

2. Warm Start:

   • Engage the chain brake.
   • Move the master control lever to the run position.
   • Pull the starter cord sharply until the engine starts.

3. Common Mistakes:

   • Over-priming the carburetor (flooding the engine).
   • Not moving the master control lever to the half-throttle position after the initial start attempt.
   • Pulling the starter cord weakly or slowly.
4. Data Point: According to Stihl’s service data, incorrect starting procedures account for up to 30% of chainsaw starting problems.
5. Actionable Advice: Practice the starting sequence until it becomes second nature. A smooth, confident pull is more effective than multiple weak attempts.
6. Real-World Example: I’ve seen many people struggle with starting their chainsaws simply because they weren’t following the correct sequence. Taking the time to learn the proper procedure can make a world of difference.

Troubleshooting Starting Problems

If your chainsaw still won’t start after following the correct sequence, here are a few things to check:

• Spark Plug: Remove the spark plug and inspect it. It should be clean and dry. If it’s fouled with carbon or wet with fuel, clean or replace it.
• Fuel Filter: Check the fuel filter in the fuel tank. If it’s clogged, replace it.
• Air Filter: A dirty air filter can restrict airflow and make starting difficult. Clean or replace it as needed.
• Spark Arrester: The spark arrester is a small screen in the muffler that prevents sparks from escaping. If it’s clogged, it can restrict exhaust flow and cause starting problems. Clean it with a wire brush.

Pro Hack #3: The Spark Plug Secret

The spark plug is a critical component of the ignition system. A worn or fouled spark plug can cause hard starting, misfires, and poor performance.

• The Problem: Over time, the spark plug electrodes can wear down, reducing the spark’s intensity. Carbon deposits can also build up on the electrodes, interfering with the spark.
• The Solution: Regularly inspect and replace the spark plug.
• Data Point: A worn spark plug can reduce engine power by up to 10%.
• Actionable Advice:
  • Check the spark plug every 25 hours of use.
  • Clean the spark plug with a wire brush or spark plug cleaner.
  • Replace the spark plug annually or more frequently if needed.
  • Use the correct spark plug for your Stihl MS171 (typically an NGK BPMR7A or equivalent).
  • Ensure the spark plug gap is correct (usually 0.020 inches or 0.5 mm).
• Real-World Example: I once had a chainsaw that was running poorly. I replaced the spark plug, and it instantly ran like new.
• Wood Science Insight: The type of wood you’re cutting can affect spark plug fouling. Cutting resinous woods like pine can lead to increased carbon buildup on the spark plug.

Checking the Spark

If you suspect a spark plug problem, you can check the spark by removing the spark plug, connecting it to the spark plug wire, and grounding the spark plug against the engine block. Pull the starter cord. You should see a strong, blue spark jumping across the spark plug gap. If the spark is weak or nonexistent, replace the spark plug or check the ignition system.

Pro Hack #4: Carburetor Care: Precision Tuning

The carburetor is responsible for mixing fuel and air in the correct proportions. A dirty or improperly adjusted carburetor can cause a variety of problems, including hard starting, poor idling, and stalling.

• The Problem: Over time, the carburetor can become clogged with dirt, varnish, and other debris. This can restrict fuel flow and affect the air-fuel mixture.
• The Solution: Regularly clean and adjust the carburetor.
• Data Point: A properly tuned carburetor can improve fuel efficiency by up to 15%.
• Actionable Advice:
  • Use fresh fuel and a fuel stabilizer to prevent varnish buildup.
  • Clean the carburetor annually or more frequently if needed.
  • Use a carburetor cleaner to remove dirt and varnish.
  • Adjust the carburetor according to the manufacturer’s instructions.
• Real-World Example: I once had a chainsaw that was idling erratically. I cleaned the carburetor and adjusted the idle speed, and it ran perfectly.

Carburetor Adjustment

The Stihl MS171 carburetor typically has two adjustment screws:

• Idle Speed Screw (LA): Adjusts the engine’s idle speed.
• High-Speed Screw (H) and Low-Speed Screw (L): These screws control the fuel mixture at high and low speeds, respectively. Note: Many newer MS171 models have fixed jets and do not allow for user adjustment of the H and L screws.

Important: Carburetor adjustment can be tricky. If you’re not comfortable doing it yourself, take your chainsaw to a qualified service technician.

Cleaning the Carburetor

1. Remove the air filter and carburetor cover.
2. Disconnect the fuel lines and throttle linkage.
3. Remove the carburetor from the engine.
4. Disassemble the carburetor carefully, noting the location of all parts.
5. Clean all parts with carburetor cleaner.
6. Reassemble the carburetor and reinstall it on the engine.

Pro Hack #5: Maintenance Matters: The Long Game

Regular maintenance is essential for keeping your Stihl MS171 running smoothly and reliably. Neglecting maintenance can lead to a variety of problems, including hard starting, poor performance, and premature wear.

• The Problem: Lack of maintenance can cause a buildup of dirt, debris, and carbon, which can interfere with the engine’s operation.
• The Solution: Follow a regular maintenance schedule.
• Data Point: Regular maintenance can extend the life of your chainsaw by up to 50%.
• Actionable Advice:
  • Clean the air filter after each use.
  • Check the spark plug every 25 hours of use.
  • Clean the carburetor annually.
  • Sharpen the chain regularly.
  • Lubricate the chain with chain oil.
  • Inspect the chainsaw for loose or damaged parts.
  • Store the chainsaw in a clean, dry place.
• Real-World Example: I’ve seen chainsaws that were still running strong after 20 years simply because they were well-maintained.
• Wood Science Insight: The type of wood you’re cutting can affect the maintenance requirements of your chainsaw. Cutting dirty or abrasive wood can lead to increased wear on the chain and other components.

Maintenance Checklist

Here’s a maintenance checklist to help you keep your Stihl MS171 in top condition:

• Daily:
  • Clean the air filter.
  • Check the chain tension.
  • Lubricate the chain.
• Weekly:
  • Sharpen the chain.
  • Inspect the spark plug.
  • Check the fuel filter.
• Annually:
  • Clean the carburetor.
  • Replace the spark plug.
  • Inspect the fuel lines.
  • Check the recoil starter.

Chain Maintenance: A Sharp Edge is Key

A dull chain can make cutting difficult and put unnecessary strain on the engine. Sharpen the chain regularly to ensure smooth, efficient cutting.

• How to Sharpen:
  • Use a chainsaw file and guide.
  • Follow the manufacturer’s instructions for the correct filing angle and depth.
  • Sharpen each tooth evenly.
• Tip: I use a chain grinder for faster and more accurate sharpening.

Chain Oil: Keeping Things Smooth

Chain oil lubricates the chain and bar, reducing friction and wear. Use a high-quality chain oil designed for chainsaws.

• Why it Matters: Insufficient lubrication can lead to premature wear of the chain and bar.
• Tip: I check the chain oil level frequently and refill it as needed.

Beyond the Hacks: Safety First!

No discussion about chainsaws is complete without emphasizing safety. Chainsaws are powerful tools that can be dangerous if used improperly.

• Essential Safety Gear:
  • Safety glasses or face shield
  • Hearing protection
  • Gloves
  • Chaps or chainsaw pants
  • Steel-toed boots

• Safe Operating Practices:

  • Read and understand the owner’s manual.
  • Never operate a chainsaw when you’re tired or under the influence of drugs or alcohol.
  • Keep a firm grip on the chainsaw with both hands.
  • Maintain a stable stance.
  • Be aware of your surroundings.
  • Never cut above your head.
  • Avoid cutting with the tip of the bar (kickback zone).
  • Use the chain brake when not actively cutting.

• Data Point: According to the U.S. Consumer Product Safety Commission, chainsaws cause approximately 30,000 injuries each year.

• Actionable Advice: Take a chainsaw safety course to learn proper operating techniques.
• Real-World Example: I’ve seen firsthand the devastating consequences of chainsaw accidents. Always prioritize safety.

Wood Selection and Preparation: Maximizing Efficiency

The type of wood you’re cutting can affect your chainsaw’s performance and longevity. Understanding the properties of different woods can help you choose the right tool for the job and optimize your cutting techniques.

Hardwood vs. Softwood

• Hardwoods: Generally denser and more difficult to cut than softwoods. Examples include oak, maple, and birch.

• Softwoods: Less dense and easier to cut than hardwoods. Examples include pine, fir, and spruce.

• Data Point: Hardwoods typically have a higher BTU (British Thermal Unit) value than softwoods, meaning they produce more heat when burned.

• Actionable Advice: Use a sharp chain and a powerful chainsaw when cutting hardwoods.
• Wood Science Insight: The density of wood is directly related to its moisture content. Green wood (freshly cut wood) is much heavier and harder to cut than seasoned wood.

Firewood Seasoning: The Key to Efficient Burning

Seasoning firewood reduces its moisture content, making it easier to ignite and burn efficiently.

• The Process:
  • Split the wood into smaller pieces.
  • Stack the wood in a well-ventilated area.
  • Allow the wood to dry for at least six months, or preferably a year.
• Data Point: Seasoned firewood can have a moisture content of 20% or less, while green firewood can have a moisture content of 50% or more.
• Actionable Advice: Cover the top of the woodpile to protect it from rain and snow.
• Real-World Example: I’ve burned both green and seasoned firewood, and the difference in performance is dramatic. Seasoned firewood burns hotter, cleaner, and produces less smoke.

Stacking Techniques:

There are several ways to stack firewood, but the goal is always the same: to promote good airflow.

• Traditional Row Stacking: Stacking the wood in rows with gaps between the rows.
• Circular Stacking (Holz Hausen): Building a circular stack with a chimney in the center.
• Crib Stacking: Building a stack with interlocking layers of wood.

The Future of Chainsaws: Technology and Innovation

The chainsaw industry is constantly evolving, with new technologies and innovations being introduced all the time.

• Battery-Powered Chainsaws: Becoming increasingly popular due to their convenience, quiet operation, and lack of emissions.
• Automatic Chain Tensioning: Simplifies chain maintenance and reduces the risk of chain slippage.
• Electronic Fuel Injection: Improves fuel efficiency and reduces emissions.

• Smart Chainsaws: Equipped with sensors and electronics that can monitor the chainsaw’s performance and provide diagnostic information.

• Data Point: The global chainsaw market is expected to reach $4.5 billion by 2027.
• Actionable Advice: Stay informed about the latest chainsaw technologies and consider upgrading to a newer model when it’s time to replace your old chainsaw.

Conclusion: Smooth Starts and Beyond

Getting smooth starts with your Stihl MS171 chainsaw is essential for a productive and enjoyable wood processing experience. By following these five pro hacks—using fresh fuel, mastering the starting sequence, maintaining the spark plug, caring for the carburetor, and performing regular maintenance—you’ll be well on your way to starting your chainsaw with confidence every time.

Remember, safety should always be your top priority. Wear appropriate safety gear and follow safe operating practices.

And finally, don’t be afraid to experiment and learn from your experiences. Wood processing is a skill that takes time and practice to master. But with a little knowledge and effort, you can become a proficient and confident chainsaw user.

So, get out there, start your chainsaw, and enjoy the satisfaction of working with wood!

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