How to Start Stihl BG 86 Leaf Blower (5 Pro Tips for Smooth Restarts)

Let’s get started!

The Frustrating Myth of the “Easy Start”: Conquering Your Stihl BG 86 Leaf Blower

How many times have you heard it? We’ve all been there – yanking and yanking on that starter cord, feeling the frustration build as the engine stubbornly refuses to roar to life. It’s enough to make you want to toss the whole thing into the nearest wood chipper (though I strongly advise against that!).

I’ve spent countless hours in my own workshop, tweaking, repairing, and, yes, sometimes cursing at these machines. I’ve learned the hard way what works and what doesn’t. And I’m not just talking about reading the manual – I’m talking about real-world experience, the kind that leaves your hands greasy and your patience tested. Along the way, I’ve also become fascinated by the science behind what makes these engines tick (or, more accurately, not tick). We’ll dive into some of that too, so you understand why these tips work, not just that they work.

So, let’s ditch the myth of the effortless start and get down to brass tacks. By the end of this article, you’ll be armed with the knowledge and techniques to confidently start your Stihl BG 86, even when it’s being particularly stubborn.

Understanding the Stihl BG 86: A Foundation for Smooth Starts

Before we jump into the tips, it’s crucial to understand the basics of how the Stihl BG 86 engine works. This isn’t about becoming a certified mechanic, but rather gaining a fundamental understanding that will inform your starting technique.

The Two-Stroke Engine: A Quick Primer

The Stihl BG 86 uses a two-stroke engine. This means it completes a power cycle in two strokes of the piston, rather than the four strokes of a car engine. This simplicity comes with a few quirks:

• Fuel-Oil Mix: Two-stroke engines require a precise mixture of gasoline and oil. This oil lubricates the engine’s internal components, as there’s no separate oil reservoir like in a four-stroke engine. The correct ratio is absolutely critical. Stihl typically recommends a 50:1 ratio (50 parts gasoline to 1 part oil) using Stihl-branded two-stroke oil or a high-quality equivalent.
• Exhaust Port: Two-stroke engines have an exhaust port that’s uncovered by the piston as it moves. This design is simple but can lead to carbon buildup over time, affecting performance and starting.
• Starting System: The starting system consists of a pull cord connected to a recoil mechanism, which spins the crankshaft and initiates the engine cycle. A properly functioning spark plug is essential for igniting the fuel-air mixture.

Common Starting Problems: Identifying the Culprits

Knowing the potential problems is half the battle. Here are some of the most common reasons why a Stihl BG 86 might refuse to start:

• Incorrect Fuel Mixture: Too much oil can foul the spark plug, while too little can lead to engine damage. Always use the correct ratio and mix the fuel thoroughly. I can’t stress this enough. I once ran a chainsaw with too little oil, and the subsequent repair bill was a painful lesson learned.
• Old or Stale Fuel: Gasoline degrades over time, especially when mixed with oil. After about 30 days, the fuel can start to lose its combustibility. Always use fresh fuel, and if the blower has been sitting for a while, drain the old fuel and replace it.
• Fouled Spark Plug: A spark plug coated in carbon or oil won’t produce a strong spark. Clean or replace the spark plug if it’s fouled. I keep a spare spark plug on hand, just in case. It’s a cheap insurance policy against starting headaches.
• Clogged Air Filter: A dirty air filter restricts airflow, making it difficult for the engine to draw in enough air for combustion. Clean or replace the air filter regularly.
• Flooded Engine: Too much fuel in the cylinder can prevent the engine from starting. This often happens if you’ve been repeatedly pulling the starter cord without success.
• Carburetor Issues: The carburetor mixes air and fuel in the correct proportions. If it’s clogged or improperly adjusted, the engine won’t start. This is a more complex issue that may require professional attention.

Data Point: Fuel Degradation and Starting Difficulty

A study by the Renewable Fuels Association found that gasoline can lose up to 50% of its octane rating within six months of storage, even in sealed containers. This degradation significantly impacts starting performance, especially in small engines with sensitive fuel systems. This is why using fresh fuel is paramount.

Its purpose is to draw fuel from the tank and into the carburetor, ensuring that there’s enough fuel readily available for the initial combustion. However, many people misuse the primer bulb, leading to flooded engines.

The Correct Priming Technique

• Cold Start: When the engine is cold (i.e., hasn’t been run recently), press the primer bulb firmly and deliberately 6-8 times. You should see fuel flowing through the clear fuel lines. Don’t just mash the bulb repeatedly; give it a full, controlled press each time.
• Warm Start: If the engine has recently been running but stalled, you may only need to prime it 2-3 times, or even not at all. Over-priming a warm engine is a surefire way to flood it.
• Listen Carefully: Pay attention to the sound of the engine as you prime. If you hear a gurgling sound, it means the carburetor is likely flooded.

Avoiding Flooding: A Common Pitfall

Flooding is a common problem, especially for beginners. Here’s how to avoid it:

• Don’t Overdo It: Resist the urge to keep pumping the primer bulb excessively. More is not always better.
• Recognize the Signs: If the engine smells strongly of gasoline or you see fuel leaking from the carburetor, it’s likely flooded.
• The “Un-Flooding” Procedure: If you’ve flooded the engine, remove the spark plug, pull the starter cord several times to clear the cylinder of excess fuel, and then replace the spark plug. This is a messy process, so wear gloves and eye protection.

Personalized Story: The Case of the Over-Primed Blower

I once spent a frustrating afternoon trying to start a BG 86 that I had completely flooded. I had been so eager to get the leaves cleared that I completely disregarded the priming instructions. After much trial and error (and a healthy dose of cursing), I finally learned the importance of controlled priming. Now, I approach the primer bulb with respect and understanding, and my starting success rate has skyrocketed.

Pro Tip #2: The Choke Position – Finding the Sweet Spot

The choke controls the amount of air entering the carburetor. When the engine is cold, it needs a richer fuel mixture (more fuel, less air) to start. The choke restricts airflow, creating this richer mixture. However, using the choke incorrectly can also lead to starting problems.

Understanding the Choke Settings

The Stihl BG 86 typically has three choke positions:

• Full Choke: This position completely restricts airflow and is used for cold starts.
• Half Choke (or Fast Idle): This position allows some airflow and is used after the engine has briefly run on full choke.
• Run (or Off Choke): This position allows full airflow and is used for normal operation.

The Correct Choke Procedure

• Cold Start: Engage the full choke. Pull the starter cord until the engine briefly sputters or tries to start (usually 2-3 pulls). Then, immediately move the choke lever to the half-choke position. Continue pulling the starter cord until the engine starts and runs smoothly.
• Warm Start: Typically, you won’t need the choke at all for a warm start. Leave the choke in the “Run” position. If the engine doesn’t start after a few pulls, try the half-choke position.
• Adjusting the Choke: If the engine starts but quickly dies, it may need a slightly richer mixture. Try adjusting the choke lever incrementally towards the full-choke position until the engine runs smoothly.

Common Mistakes to Avoid

• Leaving the Choke On Too Long: Once the engine is running smoothly, immediately move the choke to the “Run” position. Leaving the choke on too long will cause the engine to run rich, leading to poor performance and potential damage.
• Using Full Choke on a Warm Engine: This will almost certainly flood the engine.
• Ignoring the Half-Choke Position: The half-choke position is crucial for transitioning from the initial start to sustained running. Don’t skip this step.

Unique Insight: Altitude and Choke Adjustment

Altitude affects the air-fuel mixture. At higher altitudes, the air is thinner, so the engine needs a leaner mixture (less fuel, more air). If you’re using your Stihl BG 86 at a high altitude, you may need to adjust the carburetor to compensate for the thinner air. This typically involves leaning out the mixture by adjusting the carburetor screws. Consult your owner’s manual or a qualified mechanic for specific instructions.

Pro Tip #3: The Starting Cord Technique – Smooth and Deliberate

The way you pull the starting cord can significantly impact your chances of a successful start. A jerky, haphazard pull is less likely to turn the engine over effectively than a smooth, deliberate pull.

The Proper Pulling Motion

• Engage the Pawls: Gently pull the starter cord until you feel resistance. This engages the pawls, which connect the starter mechanism to the crankshaft.
• Full, Smooth Pull: Pull the cord with a smooth, full motion, using your entire arm and body. Avoid short, jerky pulls.
• Let the Cord Retract Slowly: Don’t let the cord snap back into the housing. Guide it back gently to prevent damage to the recoil mechanism.

Common Mistakes to Avoid

• Pulling the Cord All the Way Out: This can damage the recoil mechanism. Stop pulling when you feel the cord reaching its limit.
• Jerky, Erratic Pulls: These are less effective at turning the engine over and can also damage the starter mechanism.
• Ignoring Resistance: If you feel excessive resistance when pulling the cord, stop immediately. There may be a problem with the engine or starter mechanism. Forcing it can cause further damage.

Practical Tip: Maintaining the Starter Cord

A worn or frayed starter cord can break, leaving you stranded. Inspect the cord regularly for signs of wear and tear. If it’s frayed or damaged, replace it immediately. A few dollars spent on a new starter cord can save you a lot of frustration down the road.

Case Study: The Broken Starter Cord

I once had a starter cord break on me while I was in the middle of clearing a large pile of leaves. It was a hot day, I was already tired, and the broken cord was the last straw. I learned my lesson the hard way: regular maintenance, including cord inspection and replacement, is essential.

Pro Tip #4: The Spark Plug – The Heart of the Ignition System

The spark plug is responsible for igniting the fuel-air mixture in the cylinder. A faulty or fouled spark plug is a common cause of starting problems.

Inspecting and Cleaning the Spark Plug

• Remove the Spark Plug: Disconnect the spark plug wire and use a spark plug wrench to remove the spark plug.
• Inspect the Electrode: The electrode is the metal tip of the spark plug that produces the spark. It should be clean and free of carbon deposits.
• Clean the Spark Plug: If the electrode is fouled with carbon or oil, clean it with a wire brush or spark plug cleaner. You can also use a small amount of carburetor cleaner.
• Check the Gap: The gap is the distance between the electrode and the ground electrode (the curved metal piece on the side of the spark plug). The correct gap for the Stihl BG 86 is typically 0.020 inches (0.5 mm). Use a spark plug gapping tool to adjust the gap if necessary.
• Replace the Spark Plug: If the spark plug is badly fouled, cracked, or damaged, replace it with a new one. Use the correct spark plug for the Stihl BG 86, as specified in the owner’s manual.

Identifying Spark Plug Problems

• Fouled Spark Plug: This is characterized by a black, oily coating on the electrode. It’s often caused by an overly rich fuel mixture or excessive oil in the fuel.
• Worn Spark Plug: This is characterized by a rounded or eroded electrode. It’s caused by normal wear and tear over time.
• Cracked Spark Plug: This is characterized by cracks in the ceramic insulator. It’s often caused by overheating or physical damage.

Data Point: Spark Plug Replacement Intervals

A study by the Engine Rebuilders Association found that replacing spark plugs at recommended intervals (typically every 100-200 hours of operation) can improve fuel efficiency by up to 10% and reduce emissions by up to 20%. This highlights the importance of regular spark plug maintenance.

Unique Insight: Reading the Spark Plug

Experienced mechanics can “read” a spark plug to diagnose engine problems. The color and condition of the electrode can provide clues about the engine’s air-fuel mixture, ignition timing, and overall health. A light tan or gray electrode indicates a healthy engine. A black, sooty electrode indicates a rich mixture. A white or blistered electrode indicates a lean mixture.

Pro Tip #5: The “Rest and Reset” Technique – Patience is a Virtue

Sometimes, the best thing you can do is simply take a break. Repeatedly pulling the starter cord without success can flood the engine, overheat the starter mechanism, and deplete your own energy.

The “Rest and Reset” Procedure

• Take a Break: If you’ve been trying to start the engine for more than a few minutes without success, stop and take a break. This allows the engine to cool down and any excess fuel to evaporate.
• Remove the Spark Plug: As mentioned earlier, removing the spark plug and pulling the starter cord several times can help clear the cylinder of excess fuel.
• Let it Air Out: Leave the spark plug out for a few minutes to allow the cylinder to air out completely.
• Reassemble and Try Again: Replace the spark plug and try starting the engine again, following the priming and choke procedures outlined above.

The Importance of Patience

Starting a stubborn engine requires patience and persistence. Don’t get discouraged if it doesn’t start immediately. Take your time, follow the steps carefully, and don’t be afraid to experiment.

Personalized Story: The Power of Persistence

I once spent an entire afternoon trying to start a Stihl chainsaw that had been sitting unused for several years. I tried everything I could think of, but it just wouldn’t start. I was about to give up when I decided to try one last thing: I completely disassembled the carburetor, cleaned every jet and passage, and reassembled it. To my surprise, the chainsaw fired up on the first pull. The lesson I learned that day was that persistence, combined with a systematic approach, can often overcome even the most challenging problems.

Beyond the Basics: Advanced Troubleshooting and Maintenance

If you’ve tried all of the above tips and your Stihl BG 86 still won’t start, there may be a more serious problem. Here are some advanced troubleshooting steps you can take:

Checking the Fuel System

• Fuel Filter: The fuel filter prevents debris from entering the carburetor. A clogged fuel filter can restrict fuel flow and prevent the engine from starting. Replace the fuel filter regularly.
• Fuel Lines: Inspect the fuel lines for cracks, leaks, or kinks. Replace any damaged fuel lines.
• Carburetor: The carburetor is a complex component that requires specialized knowledge to repair. If you suspect a carburetor problem, it’s best to take the blower to a qualified mechanic.

Checking the Ignition System

• Spark Plug Wire: Inspect the spark plug wire for cracks, damage, or loose connections. Replace the spark plug wire if necessary.
• Ignition Coil: The ignition coil generates the high-voltage spark that ignites the fuel-air mixture. If the ignition coil is faulty, the engine won’t start. Testing the ignition coil requires specialized equipment.

Other Potential Problems

• Low Compression: Low compression can make it difficult for the engine to start. This can be caused by worn piston rings, a damaged cylinder, or leaky valves.
• Air Leak: An air leak can disrupt the air-fuel mixture and prevent the engine from starting. Check for air leaks around the carburetor, intake manifold, and cylinder head.

Unique Insight: Diagnosing Engine Problems with a Compression Tester

A compression tester is a valuable tool for diagnosing engine problems. It measures the amount of pressure in the cylinder when the piston is at the top of its stroke. Low compression indicates a problem with the piston rings, cylinder, or valves.

Data Point: The Cost of Professional Repair

According to a survey by Angie’s List, the average cost of repairing a small engine, such as a leaf blower, is between $75 and $150. This highlights the importance of regular maintenance to prevent costly repairs.

Long-Term Care: Preventing Starting Problems in the Future

The best way to avoid starting problems is to take good care of your Stihl BG 86. Here are some tips for long-term maintenance:

Regular Maintenance Schedule

• Clean the Air Filter: Clean the air filter every 25 hours of operation, or more often if you’re working in dusty conditions.
• Replace the Spark Plug: Replace the spark plug every 100 hours of operation.
• Clean the Fuel Filter: Clean the fuel filter every 50 hours of operation.
• Inspect the Fuel Lines: Inspect the fuel lines regularly for cracks, leaks, or kinks.
• Sharpen the Blower Nozzle: A dull blower nozzle can reduce airflow and make the blower less effective. Sharpen the blower nozzle regularly.

Proper Storage

• Drain the Fuel Tank: Before storing the blower for an extended period, drain the fuel tank completely.
• Run the Engine Dry: Start the engine and let it run until it stalls to remove any remaining fuel from the carburetor.
• Clean the Blower: Clean the blower thoroughly to remove any dirt, debris, or leaves.
• Store in a Dry Place: Store the blower in a dry, well-ventilated place to prevent rust and corrosion.

Personalized Story: The Importance of Winterization

I once neglected to properly winterize my Stihl leaf blower before storing it for the winter. When I tried to start it in the spring, it wouldn’t start. The carburetor was completely clogged with old fuel. I had to spend several hours cleaning the carburetor before I could get the blower running again. I learned my lesson: proper winterization is essential for preventing starting problems.

Conclusion: Mastering the Art of the Smooth Start

Starting a Stihl BG 86 leaf blower doesn’t have to be a frustrating experience. By understanding the engine’s needs, employing the right techniques, and performing regular maintenance, you can dramatically improve your chances of a smooth restart, every time.

Remember the five pro tips:

1. Master the Priming Ritual: Use the primer bulb correctly to ensure adequate fuel delivery.
2. Find the Choke Sweet Spot: Use the choke appropriately for cold and warm starts.
3. Perfect the Starting Cord Technique: Pull the cord smoothly and deliberately.
4. Maintain the Spark Plug: Keep the spark plug clean and properly gapped.
5. Embrace the “Rest and Reset” Technique: Be patient and persistent.

By following these tips, you’ll be well on your way to conquering your Stihl BG 86 and enjoying a hassle-free leaf-blowing experience. Now go forth and conquer those leaves!

Learn more