Stihl Weed Eater FS 90: Best Choice for Firewood Prep (3 Pro Tips)

“I’ve been struggling to clear brush and small trees around my property, and I need something that can handle tough weeds and also help with preparing smaller pieces of wood for kindling. I’ve heard good things about the Stihl FS 90. Is it really a good choice, and what are the best ways to use it for firewood prep?”

That’s a question I hear a lot. Let’s dive deep into why the Stihl FS 90 weed eater might be your best bet for tackling those overgrown areas and getting a head start on your firewood prep, and I will share three pro tips to maximize its utility. I’ll share my own experiences and observations, and give you actionable advice to make your work easier and more efficient.

Stihl FS 90: Your Versatile Firewood Prep Companion

The Stihl FS 90 isn’t just a weed eater; it’s a versatile tool that can significantly aid in firewood preparation. I’ve personally used it for years, and I’ve found it to be an indispensable part of my firewood processing arsenal. Its power, durability, and adaptability make it ideal for various tasks beyond just trimming grass.

Why the Stihl FS 90 Stands Out

The FS 90 is powered by a robust, fuel-efficient engine, which provides ample power for cutting through thick weeds, brush, and even small trees. Its solid construction ensures it can withstand the rigors of regular use, making it a reliable choice for both homeowners and professionals.

One of the key advantages of the FS 90 is its compatibility with various attachments. This allows you to transform it from a simple weed eater into a multi-functional tool capable of handling different tasks. For firewood prep, the brush knife attachment is particularly useful.

Key Features of the Stihl FS 90

• Engine Power: Typically around 1.3 horsepower, providing enough power for demanding tasks.
• Fuel Capacity: Approximately 0.53 liters, allowing for extended run times.
• Weight: Around 5.8 kg (without cutting attachment), making it manageable for extended use.
• Attachment Compatibility: Compatible with various Stihl attachments, including brush knives and circular saw blades.
• Ergonomic Design: Designed for user comfort, reducing fatigue during prolonged use.

Pro Tip 1: Mastering the Brush Knife Attachment

The brush knife attachment is what truly unlocks the firewood prep potential of the Stihl FS 90. It’s designed to cut through thicker vegetation, making it perfect for clearing small trees and branches that are ideal for kindling.

Choosing the Right Brush Knife

Not all brush knives are created equal. I’ve found that a blade with 8 teeth offers a good balance of cutting power and safety. Blades with fewer teeth tend to be more aggressive, while those with more teeth provide a cleaner cut.

• 8-Tooth Blade: Ideal for general-purpose use, offering a good balance of cutting power and safety.
• 4-Tooth Blade: More aggressive, suitable for thicker vegetation, but requires more caution.
• Circular Saw Blade: Designed for cutting wood, but can be more dangerous if not used properly.

Installing the Brush Knife

Installing the brush knife is straightforward, but it’s crucial to follow the manufacturer’s instructions to ensure safety. Here’s a step-by-step guide:

1. Remove the String Trimmer Head: Use the appropriate tool to remove the existing string trimmer head.
2. Install the Mounting Plate: Place the mounting plate onto the shaft, ensuring it aligns correctly.
3. Attach the Brush Knife: Position the brush knife onto the mounting plate, making sure it’s securely seated.
4. Secure with the Nut: Tighten the nut to secure the brush knife in place.
5. Test the Assembly: Before use, manually rotate the brush knife to ensure it spins freely and is properly aligned.

Techniques for Cutting Small Trees and Branches

When using the brush knife, safety is paramount. Always wear appropriate personal protective equipment (PPE), including eye protection, hearing protection, gloves, and sturdy boots.

• Clearing Small Trees: Approach the tree from the side, using a sweeping motion to cut through the trunk. Start with small cuts, gradually working your way through the tree.
• Cutting Branches: Support the branch with one hand while cutting with the brush knife. Avoid cutting branches that are under tension, as they can spring back and cause injury.
• Creating Kindling: Cut the cleared branches into smaller pieces, typically 6-12 inches in length. These pieces are perfect for kindling, helping you start your fires quickly and easily.

Real-World Example

I once had a customer, John, who was struggling to clear a heavily overgrown area on his property. He had tried using a standard weed eater, but it was no match for the thick brush and small trees. I recommended the Stihl FS 90 with the brush knife attachment.

After a few hours of work, John had cleared the entire area. He was amazed at how easily the FS 90 cut through the vegetation. He even used the cleared branches to create a large pile of kindling, which he used throughout the winter.

Takeaway

Mastering the brush knife attachment is essential for maximizing the firewood prep capabilities of the Stihl FS 90. By choosing the right blade, installing it correctly, and using proper cutting techniques, you can efficiently clear small trees and branches for kindling.

Pro Tip 2: Optimizing Fuel and Maintenance

The performance and longevity of your Stihl FS 90 depend heavily on proper fuel and maintenance practices. Using the right fuel mix and following a regular maintenance schedule will ensure your weed eater runs smoothly and reliably for years to come.

Fueling Your Stihl FS 90

Stihl recommends using a high-quality, 89-octane gasoline mixed with Stihl 2-stroke engine oil. The recommended fuel-to-oil ratio is 50:1. This means for every 50 parts of gasoline, you should add 1 part of oil.

• Gasoline: Use unleaded gasoline with a minimum octane rating of 89.
• 2-Stroke Oil: Use Stihl 2-stroke engine oil for optimal performance and engine protection.
• Fuel-to-Oil Ratio: Mix gasoline and oil at a 50:1 ratio.

I always recommend using a fuel stabilizer, especially if you’re not going to use the weed eater for an extended period. Fuel stabilizer helps prevent the gasoline from breaking down and causing deposits in the carburetor.

Maintaining Your Stihl FS 90

Regular maintenance is crucial for keeping your Stihl FS 90 in top condition. Here’s a maintenance schedule I recommend:

• Daily:
  • Check the air filter and clean if necessary.
  • Inspect the cutting attachment for damage and replace if needed.
  • Check the fuel lines for leaks.
• Weekly:
  • Clean the spark plug and check the gap.
  • Grease the gear head.
  • Sharpen the brush knife.
• Monthly:
  • Clean the carburetor.
  • Inspect the fuel filter and replace if necessary.
  • Check the muffler for carbon buildup.

Cleaning the Air Filter

A dirty air filter can restrict airflow to the engine, reducing performance and potentially causing damage. To clean the air filter:

1. Remove the Air Filter Cover: Locate the air filter cover and remove it.
2. Remove the Air Filter: Carefully remove the air filter from the housing.
3. Clean the Air Filter: Tap the air filter gently to remove loose dirt and debris. You can also wash it with warm, soapy water.
4. Dry the Air Filter: Allow the air filter to dry completely before reinstalling it.
5. Reinstall the Air Filter: Place the air filter back into the housing and reinstall the air filter cover.

Sharpening the Brush Knife

A sharp brush knife is essential for efficient cutting. A dull blade will require more effort and can be more dangerous. To sharpen the brush knife:

1. Secure the Blade: Clamp the blade in a vise to hold it securely.
2. Use a File: Use a flat file to sharpen the cutting edges of the blade.
3. Maintain the Angle: Maintain the original angle of the cutting edge as you sharpen.
4. Check for Burrs: Remove any burrs from the cutting edge using a fine file or honing stone.

Case Study

I once had a client, Sarah, who was experiencing poor performance with her Stihl FS 90. She had been using it for several years but had never performed any maintenance. I inspected the weed eater and found that the air filter was completely clogged, the spark plug was fouled, and the brush knife was dull.

I cleaned the air filter, replaced the spark plug, sharpened the brush knife, and performed a carburetor cleaning. After the maintenance, Sarah’s Stihl FS 90 ran like new. She was amazed at the difference proper maintenance made.

Takeaway

Optimizing fuel and maintenance practices is crucial for ensuring the performance and longevity of your Stihl FS 90. By using the right fuel mix and following a regular maintenance schedule, you can keep your weed eater running smoothly and reliably for years to come.

Pro Tip 3: Adapting Techniques for Firewood Processing

While the Stihl FS 90 with a brush knife isn’t a replacement for a chainsaw or log splitter, it can be a valuable tool for preparing smaller pieces of wood for kindling and managing the debris generated during firewood processing.

Clearing Debris and Small Branches

One of the most time-consuming aspects of firewood processing is dealing with the debris and small branches that are left behind. The Stihl FS 90 can be used to quickly and efficiently clear these materials.

• Gathering Debris: Use the brush knife to sweep debris into piles.
• Cutting Small Branches: Cut small branches into manageable lengths for disposal or kindling.
• Creating Neat Stacks: Use the weed eater to trim vegetation around firewood stacks, creating a neat and organized storage area.

Preparing Kindling

Kindling is essential for starting fires, and the Stihl FS 90 can be used to create a steady supply. By cutting small branches into 6-12 inch lengths, you can easily create kindling that will ignite quickly and easily.

• Selecting Suitable Branches: Choose dry, small-diameter branches for kindling.
• Cutting to Length: Use the brush knife to cut the branches into 6-12 inch lengths.
• Splitting Kindling: For thicker pieces, use a hatchet or small splitting axe to split the kindling into smaller pieces.

Utilizing the FS 90 in Conjunction with Other Tools

The Stihl FS 90 is most effective when used in conjunction with other firewood processing tools, such as a chainsaw and log splitter. Here’s how I integrate it into my firewood processing workflow:

1. Felling Trees: Use a chainsaw to fell trees.
2. Limbing: Use the chainsaw to remove the larger limbs.
3. Clearing Small Branches: Use the Stihl FS 90 to clear the smaller branches and debris.
4. Bucking: Use the chainsaw to cut the logs into firewood lengths.
5. Splitting: Use a log splitter to split the firewood.
6. Preparing Kindling: Use the Stihl FS 90 to prepare kindling from the smaller branches.

Safety Considerations

When using the Stihl FS 90 for firewood processing, it’s important to prioritize safety. Always wear appropriate PPE and follow these safety guidelines:

• Eye Protection: Wear safety glasses or a face shield to protect your eyes from flying debris.
• Hearing Protection: Wear earplugs or earmuffs to protect your hearing.
• Gloves: Wear sturdy gloves to protect your hands.
• Sturdy Boots: Wear sturdy boots to protect your feet and ankles.
• Proper Clothing: Wear long pants and a long-sleeved shirt to protect your skin.
• Clear the Area: Make sure the area is clear of people and obstacles before operating the weed eater.
• Maintain a Safe Distance: Keep a safe distance from the cutting attachment.
• Avoid Overreaching: Avoid overreaching or working in awkward positions.
• Take Breaks: Take frequent breaks to avoid fatigue.

Personal Experience

I remember one time when I was helping a friend process firewood. We had felled several trees and were in the process of bucking and splitting the logs. The area was covered in small branches and debris, making it difficult to move around.

I grabbed my Stihl FS 90 and quickly cleared the area. My friend was amazed at how much faster and easier it was to work in a clean environment. We were able to process the firewood much more efficiently, thanks to the Stihl FS 90.

Takeaway

Adapting techniques for firewood processing can significantly enhance the efficiency and organization of your firewood operations. By using the Stihl FS 90 to clear debris, prepare kindling, and work in conjunction with other tools, you can streamline your workflow and create a safer, more productive environment.

Advanced Techniques and Considerations

Now that we’ve covered the basics, let’s delve into some advanced techniques and considerations to further optimize your use of the Stihl FS 90 for firewood prep.

Different wood types have varying densities, moisture contents, and resin levels, which affect their ability to ignite and burn.

• Softwoods: Softwoods like pine, fir, and cedar are excellent for kindling due to their high resin content and low density. They ignite easily and burn quickly, making them ideal for starting fires.
• Hardwoods: Hardwoods like oak, maple, and birch are denser and have lower resin content than softwoods. They are better suited for firewood because they burn longer and produce more heat. However, they can be more difficult to ignite as kindling.
• Moisture Content: The moisture content of the wood is crucial. Dry wood ignites more easily and burns more efficiently than wet wood. Aim for a moisture content of 20% or less for optimal kindling performance.

Customizing Attachments for Specific Tasks

While the brush knife is the primary attachment for firewood prep, there are other attachments that can be useful for specific tasks.

• String Trimmer Head: Use the string trimmer head for trimming grass and weeds around firewood stacks.
• Edger Attachment: Use the edger attachment to create clean edges along pathways and gardens.
• Cultivator Attachment: Use the cultivator attachment to till soil and prepare garden beds.

By customizing your Stihl FS 90 with different attachments, you can create a versatile tool that can handle a wide range of tasks around your property.

Troubleshooting Common Issues

Even with proper maintenance, you may encounter occasional issues with your Stihl FS 90. Here are some common problems and their solutions:

• Engine Won’t Start:
  • Check the fuel level and make sure the fuel is fresh.
  • Check the spark plug and replace if necessary.
  • Clean the air filter.
  • Clean the carburetor.
• Engine Runs Poorly:
  • Check the air filter and clean if necessary.
  • Check the spark plug and replace if necessary.
  • Adjust the carburetor settings.
• Cutting Attachment Won’t Rotate:
  • Check the drive shaft for damage.
  • Check the gear head for lubrication.
  • Replace the cutting attachment if it’s damaged.

Environmental Considerations

When processing firewood, it’s important to consider the environmental impact of your activities.

• Sustainable Harvesting: Harvest trees sustainably to ensure the long-term health of the forest.
• Proper Disposal of Waste: Dispose of waste materials properly, including used oil, fuel, and damaged parts.
• Erosion Control: Implement erosion control measures to prevent soil erosion and water pollution.
• Fire Safety: Take precautions to prevent wildfires, especially during dry conditions.

Advanced Case Study

I worked with a local tree service company that was looking for a more efficient way to process the debris generated during tree removal operations. They were using a chipper to dispose of the larger branches, but they were struggling to deal with the smaller branches and debris.

I recommended using the Stihl FS 90 with the brush knife attachment to clear the smaller branches and debris. The company purchased several FS 90s and trained their employees on how to use them safely and efficiently.

The results were impressive. The company was able to clear the debris much faster and more efficiently, reducing their labor costs and improving their overall productivity. They also found that the FS 90 was useful for preparing kindling for their customers.

Takeaway

By understanding wood types, customizing attachments, troubleshooting common issues, and considering environmental factors, you can further optimize your use of the Stihl FS 90 for firewood prep and related tasks.

Final Thoughts

The Stihl FS 90 is more than just a weed eater; it’s a versatile tool that can significantly aid in firewood preparation. By mastering the brush knife attachment, optimizing fuel and maintenance, and adapting techniques for firewood processing, you can unlock the full potential of this powerful tool.

Remember, safety is paramount. Always wear appropriate PPE and follow safety guidelines when operating the Stihl FS 90. With proper care and maintenance, your FS 90 will provide years of reliable service, helping you tackle a wide range of tasks around your property.

Whether you’re a homeowner looking to clear brush and prepare kindling or a professional firewood producer seeking to improve efficiency, the Stihl FS 90 is an excellent choice. Embrace its versatility, follow these pro tips, and you’ll be well on your way to mastering firewood prep.

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