5 Common STIHL FS 38 Problems: In-Depth Solutions

When it comes to yard maintenance and landscaping, the STIHL FS 38 trimmer has earned its reputation as a reliable and popular choice for homeowners and professionals alike. This lightweight and user-friendly tool is designed to keep your lawn looking immaculate.

However, even the best equipment can encounter issues from time to time. In this guide, we’ll delve into five common STIHL FS 38 problems and provide in-depth solutions to help you keep your trimmer in optimal working condition. Let’s get started by exploring the importance of addressing these issues and the significance of “STIHL FS 38.”

The Significance of the STIHL FS 38

The STIHL FS 38 is a versatile and lightweight grass trimmer known for its durability and performance. Its popularity among homeowners and professionals stems from its ability to tackle a variety of yard maintenance tasks with ease. This trimmer’s reliability makes it an essential tool for maintaining lawns, gardens, and landscapes.

Addressing Common Problems

Like any mechanical tool, the STIHL FS 38 may encounter common problems over time, affecting its performance and longevity. It’s crucial to address these issues promptly to ensure your trimmer continues to operate at its best. By addressing these common problems, you’ll save time and money on repairs while maintaining the functionality of your STIHL FS 38.

Common Problems with the STIHL FS 38

In this section of our comprehensive guide on the STIHL FS 38 trimmer, we’ll dive deep into the five most common problems that users may encounter. From engine starting issues to fuel and carburetor problems, we’ll provide detailed explanations and solutions for each of these concerns. Let’s get started by addressing the first common issue: engine starting problems.

Problem 1: Engine Starting Issues of the STIHL FS 38

Common Reasons for Difficulty Starting the Engine

1. Stale Fuel: One of the most common culprits behind engine starting problems is stale fuel. Over time, gasoline can become less effective, making it challenging to ignite the engine. It’s essential to use fresh fuel with the right oil-to-gas ratio for your STIHL FS 38.

2. Clogged Air Filter: A clogged air filter restricts air intake, which can affect the air-fuel mixture and, consequently, the engine’s starting capability. Regularly inspect and clean or replace the air filter as needed.

3. Flooded Engine: Over-priming or pulling the starter cord too many times can flood the engine with fuel, making it difficult to start. Follow the correct starting procedure to avoid this issue.

Potential Solutions

1. Fuel Mix: Ensure that you use a high-quality gasoline-oil mixture, adhering to the manufacturer’s recommendations. This will help your engine start smoothly.

2. Clean or Replace Air Filter: Regularly inspect the air filter. If it’s dirty, clean it or replace it if it’s too worn out. A clean air filter allows for proper airflow.

3. Follow Proper Starting Procedure: Pay attention to the recommended starting procedure in your STIHL FS 38 manual. Avoid excessive priming or pulling of the starter cord.

Now, let’s move on to the second common problem: trimmer line breakage.

Problem 2: Trimmer Line Breakage

Why Trimmer Line Breakage Occurs

1. Excessive Line Wear: Trimmer lines naturally wear down over time, becoming more prone to breakage. This can occur due to prolonged use or striking hard objects like rocks or fences.

2. Incorrect Line Size: Using the wrong trimmer line size can lead to breakage. Make sure you’re using the recommended line size for your STIHL FS 38.

3. Spool Issues: Sometimes, problems with the trimmer head or spool can lead to line breakage. Ensure these components are in good working condition.

Tips to Prevent and Address Trimmer Line Breakage

1. Use the Right Line Size: Always use the manufacturer-recommended trimmer line size for your FS 38 to minimize breakage.

2. Trim with Caution: Avoid striking hard objects that can wear down or break the line. Take it slow and be mindful of your surroundings.

3. Inspect the Trimmer Head: Regularly check the trimmer head and spool for any issues. Replace them if they are damaged or worn.

Now, let’s explore the third common issue: overheating.

Problem 3: Overheating

Signs of an Overheating STIHL FS 38

1. Hot to the Touch: If your trimmer becomes excessively hot to the touch during operation, it’s a sign of overheating.

2. Reduced Performance: Overheating can lead to reduced trimming performance, making your FS 38 less effective at cutting grass.

Solutions to Prevent and Manage Overheating

1. Proper Cooling: Ensure that the cooling fins are clean and free from debris. Proper airflow is crucial for preventing overheating.

2. Check for Fuel Issues: Ensure your fuel mix is correct and clean. An incorrect fuel mixture or dirty fuel can lead to overheating.

3. Adjust Cutting Techniques: Use the correct cutting techniques and avoid pushing the trimmer too hard, which can cause the engine to overwork and overheat.

Now, let’s move on to the fourth common problem: poor trimming performance.

Problem 4: Poor Trimming Performance

Reasons Behind Poor Trimming Performance

1. Dull Trimmer Line: A dull or worn-out trimmer line will struggle to cut effectively, leading to poor trimming performance.

2. Improper Line Loading: If the trimmer line isn’t loaded correctly, it can lead to uneven cutting or no cutting at all.

3. Trimmer Head Issues: Problems with the trimmer head or spool can affect its rotation and cutting performance.

Maintenance and Adjustments to Enhance Trimmer Performance

1. Replace Trimmer Line: Regularly replace the trimmer line with a fresh one to ensure sharp cutting.

2. Proper Line Loading: Follow the manufacturer’s instructions for loading the trimmer line correctly.

3. Inspect the Trimmer Head: Check the trimmer head and spool for any issues. Replace them if necessary.

Finally, let’s tackle the fifth common issue: fuel and carburetor problems.

Problem 5: Fuel and Carburetor Issues

Common Fuel and Carburetor Problems with the FS 38

1. Clogged Carburetor: A clogged carburetor can disrupt the fuel-air mixture and result in poor engine performance.

2. Dirty Fuel Filters: Dirty or clogged fuel filters can restrict the flow of fuel, leading to problems with the engine.

3. Stale Fuel: Stale or old fuel can cause varnish and carbon buildup in the carburetor, affecting its operation.

Detailed Steps for Cleaning and Troubleshooting Fuel and Carburetor Components

1. Cleaning the Carburetor: Follow your FS 38’s manual to clean the carburetor properly. This may involve disassembly and cleaning of its components.

2. Replacing Fuel Filters: If your fuel filters are dirty or clogged, replace them to ensure proper fuel flow.

3. Using Fresh Fuel: Always use fresh fuel with the correct oil-to-gas ratio to prevent carbon buildup and varnish in the carburetor.

By addressing these common problems with the STIHL FS 38 in a thorough and systematic manner, you can ensure that your trimmer continues to deliver reliable performance.

Stay tuned for the next sections of our guide, where we’ll provide more maintenance tips and a maintenance schedule to help you keep your STIHL FS 38 in top condition.

In-Depth Solutions of the STIHL FS 38

In the previous section, we delved into the five common problems STIHL FS 38 users may face and provided insights into the reasons behind these issues. Now, it’s time to explore in-depth solutions for each problem to help you keep your trimmer in optimal working condition. Let’s begin with problem 1: engine starting issues.

Engine Starting Solutions

Properly Mixing Fuel

One of the key factors for ensuring a smooth engine start is to use the right fuel mixture. The STIHL FS 38 requires a precise mix of gasoline and oil for its two-stroke engine. Here’s how to do it:

  1. Gather Supplies: You’ll need fresh gasoline and two-stroke engine oil that’s suitable for outdoor power equipment.
  2. Mixing Ratio: Check your FS 38 manual for the manufacturer’s recommended mixing ratio. Common ratios are 50:1 or 40:1 (gasoline to oil).
  3. Use a Fuel Container: A dedicated fuel container with markings for different ratios can help you achieve the correct mix. Pour in the required amount of gasoline first.
  4. Add the Oil: Slowly pour the appropriate amount of two-stroke engine oil into the gasoline.
  5. Mix Thoroughly: Seal the container and shake it vigorously to ensure a proper blend of gasoline and oil.

Maintaining the Spark Plug

A well-maintained spark plug is crucial for easy engine starting. Here’s how to maintain and replace it when needed:

  1. Inspect Regularly: Check the spark plug for signs of wear, deposits, or damage. If it’s fouled or worn out, it should be replaced.
  2. Gap Adjustment: Ensure the spark plug gap is set correctly. Check your FS 38 manual for the recommended gap size and use a gap tool to adjust it if necessary.
  3. Cleaning: Use a wire brush or a specialized spark plug cleaner to clean any carbon deposits or debris from the spark plug.
  4. Replacement: If the spark plug is too worn or damaged, it’s best to replace it with a new one. Make sure to use a spark plug recommended by the manufacturer.

Now, let’s move on to problem 2: trimmer line maintenance.

Trimmer Line Maintenance of the STIHL FS 38

Tips for Preventing Trimmer Line Breakage

Preventing trimmer line breakage starts with proper care and usage. Here are some tips to help you avoid this common issue:

  1. Select the Right Line: Always use the trimmer line size recommended by the manufacturer. Using the wrong size can cause breakage.
  2. Avoid Hard Objects: Be mindful of your surroundings and avoid trimming near hard objects like rocks, fences, or concrete. Trim with care around these areas.
  3. Correct Cutting Techniques: Use the proper cutting techniques. Tilt the trimmer head slightly for a cleaner cut. Avoid excessive force, as it can lead to line breakage.
  4. Regular Inspections: Periodically inspect the trimmer line for wear and replace it when it becomes too short or damaged.

Replacing and Maintaining the Trimmer Line

Knowing how to replace and maintain the trimmer line is essential for uninterrupted operation. Follow these steps:

  1. Safety First: Before any maintenance, make sure the trimmer is turned off, and the spark plug wire is disconnected to prevent accidental starts.
  2. Empty the Spool: If there’s any remaining line on the spool, remove it.
  3. Select the Right Line: Choose a replacement line of the correct size, as specified in your FS 38 manual.
  4. Thread the Line: Insert the trimmer line into the trimmer head following the arrows that indicate the correct winding direction.
  5. Wind the Line: Wind the line evenly and snugly on the spool. Leave a little extra line outside for cutting.
  6. Secure the Line: Tuck the ends of the line into the retainer slots on the spool to secure it.
  7. Reassemble: Put the spool back into the trimmer head and reattach it securely.

With the right line and proper maintenance, you can keep your trimmer line in good condition for efficient trimming. Now, let’s tackle problem 3: preventing overheating.

Preventing Overheating

Strategies to Prevent Overheating

Preventing your STIHL FS 38 from overheating requires careful operation and maintenance. Here are some strategies:

  1. Clean Air Filter: Regularly check and clean or replace the air filter to ensure proper airflow. A clogged filter can lead to overheating.
  2. Avoid Overworking: Don’t push the trimmer too hard. Use the appropriate cutting techniques, and let the trimmer do the work.
  3. Proper Fuel Mix: Ensure you use the correct fuel mixture with clean, fresh fuel. An incorrect mix or dirty fuel can contribute to overheating.
  4. Cooling Fins: Keep the cooling fins on the engine clean and free from debris. Proper airflow helps dissipate heat.

Cooling the Trimmer Down During Use

If you notice your trimmer is overheating during use, follow these steps to cool it down:

  1. Release Throttle: Release the throttle trigger and allow the trimmer to idle for a few moments.
  2. Check for Blockages: Inspect the cooling fins and air filter for any blockages. Remove any debris to restore proper airflow.
  3. Reduce Load: Reduce the workload by cutting less dense vegetation or allowing the trimmer to cool down before continuing.

By following these strategies and taking steps to cool the trimmer down as needed, you can prevent overheating and extend the life of your STIHL FS 38. Next, let’s focus on problem 4: improving trimming performance.

Improving Trimming Performance

Adjustments and Maintenance for Enhanced Performance

To ensure your STIHL FS 38 delivers top-notch trimming performance, follow these adjustments and maintenance procedures:

  1. Sharp Trimmer Line: Regularly replace the trimmer line to ensure it’s sharp and effective at cutting. Dull lines result in poor trimming performance.
  2. Line Loading: Always load the trimmer line correctly, following the manufacturer’s instructions. Properly loaded line feeds smoothly and cuts effectively.
  3. Trimming Head Maintenance: Check the trimmer head and spool for wear and tear. If you notice any damage, replace them to maintain proper rotation.
  4. Proper Cutting Techniques: Utilize the right cutting techniques by tilting the trimmer head slightly for improved performance. Avoid forcing the trimmer, as it can lead to overheating and reduced trimming effectiveness.
  5. Regular Cleaning: After each use, clean the trimmer head and remove any grass or debris that may accumulate. This ensures that the trimmer functions at its best during the next use.
  6. Inspect for Wear: Periodically inspect the cutting blades or trimmer head for signs of wear, and replace them when necessary to maintain optimal performance.

By adhering to these guidelines, you can significantly enhance the trimming performance of your STIHL FS 38 and keep your lawn or garden in pristine condition. Now, let’s address the final common problem: fuel and carburetor maintenance.

Fuel and Carburetor Maintenance

Cleaning and Troubleshooting Fuel and Carburetor Issues

To maintain your STIHL FS 38’s fuel and carburetor components and ensure proper operation, follow these steps:

Cleaning the Carburetor: If you suspect a clogged or dirty carburetor, it’s essential to clean it. Here’s how:

  • First, turn off the trimmer and disconnect the spark plug wire for safety.
  • Remove the air filter cover and the air filter.
  • Unscrew and remove the carburetor cover.
  • Use a carburetor cleaner to spray and clean the carburetor components.
  • Reassemble the carburetor, air filter, and cover.

Inspect Fuel Filters: Check the fuel filters for clogs or damage. If you notice any issues, replace them to ensure proper fuel flow.

Using Fresh Fuel: Always use fresh, high-quality fuel with the correct oil-to-gas ratio as specified in your FS 38 manual. Stale or improperly mixed fuel can lead to carburetor problems.

Safety Precautions: When working with fuel and carburetor components, take safety precautions. Work in a well-ventilated area, wear safety goggles and gloves and keep open flames or sparks away from the work area.

By following these instructions for fuel and carburetor maintenance, you can keep your STIHL FS 38 engine running smoothly and avoid common fuel-related issues. Your trimmer will perform optimally, providing you with efficient and reliable operation for all your lawn maintenance needs.

In the next sections of our guide, we’ll provide additional maintenance tips to keep your STIHL FS 38 in top condition, as well as a maintenance schedule to help you stay on top of essential maintenance tasks. Stay tuned for more expert advice on maximizing the performance and lifespan of your trimmer.

Maintenance Tips of the STIHL FS 38

In our previous sections, we’ve explored the most common problems that STIHL FS 38 users may encounter and provided comprehensive solutions for each issue. Now, to ensure that your trimmer continues to operate at its best, we’ll offer some general maintenance tips and provide a maintenance schedule that you can follow. Let’s begin with essential maintenance tips.

General Maintenance Tips

Maintaining your STIHL FS 38 is crucial to keep it in top condition. Regular care and attention will not only prevent problems but also extend the life of your trimmer. Here are some general maintenance tips:

1. Regular Cleaning

After each use, take a moment to clean your STIHL FS 38. Remove grass clippings, dirt, and debris from the trimmer head, air filter, and cooling fins. A clean trimmer operates more efficiently and is less likely to overheat.

2. Check for Wear and Tear

Periodically inspect your trimmer for signs of wear and tear. Examine the trimmer line, cutting blades, trimmer head, and spool. If you notice any damage or excessive wear, replace the affected parts promptly to maintain optimal performance.

3. Keep the Air Filter Clean

A clean air filter is essential for the engine’s performance. Regularly inspect the air filter and clean or replace it as needed. A clogged filter restricts airflow, which can lead to engine problems.

4. Tighten Loose Fasteners

Vibrations from the operation can loosen fasteners over time. Check the trimmer for loose screws, nuts, and bolts, and tighten them as necessary. This ensures safety and prevents parts from falling off during use.

5. Store Properly

When storing your STIHL FS 38 for an extended period, take the following steps:

  • Drain the fuel tank or use a fuel stabilizer to prevent fuel deterioration.
  • Remove and clean the spark plug.
  • Store the trimmer in a dry, cool place, away from direct sunlight.

Maintenance Schedule

To help you stay on top of essential maintenance tasks and ensure the longevity and performance of your STIHL FS 38, we’ve prepared a maintenance schedule. Adhering to this schedule will keep your trimmer in peak condition:

Daily Maintenance

  1. After Use Cleaning: Clean the trimmer, removing grass clippings, dirt, and debris.
  2. Inspect Trimmer Line: Check the condition of the trimmer line, and replace it if it’s too worn or damaged.

Weekly Maintenance

  1. Air Filter Check: Inspect the air filter for dirt and debris. Clean or replace it if necessary.
  2. Fastener Check: Look for loose screws, nuts, and bolts and tighten them.
  3. Cooling Fins Inspection: Check the cooling fins for blockages or debris and clean them if needed.

Monthly Maintenance

  1. Spark Plug Inspection: Examine the spark plug for wear or fouling. Clean or replace it as required.
  2. Trimmer Head Examination: Inspect the trimmer head and spool for wear and tear. Replace any damaged components.

Seasonal Maintenance

  1. Fuel Tank Maintenance: At the end of each season, either drain the fuel tank or use a fuel stabilizer to preserve the fuel.
  2. End-of-Season Storage: Before storing your trimmer for the off-season, clean it, remove the spark plug, and store it in a cool, dry place.

By following this maintenance schedule, you’ll keep your STIHL FS 38 in excellent working condition, prevent common problems, and enjoy many years of reliable operation. Regular maintenance is the key to extending the lifespan of your trimmer and ensuring it performs at its best when you need it most.

Stay tuned for more expert advice and tips in the final section of our guide, where we’ll offer a summary and conclusion, emphasizing the importance of addressing common STIHL FS 38 problems and maintaining this fantastic trimmer effectively.


We’ve journeyed through the world of the STIHL FS 38 trimmer, uncovering the most common problems users may face and providing detailed solutions for each issue. As we conclude this comprehensive guide, it’s essential to understand the significance of addressing these common problems and how the solutions we’ve offered can help you maintain your trimmer effectively.

The Importance of Addressing Common Problems

Owning an STIHL FS 38 trimmer brings with it the promise of a powerful, versatile tool for maintaining your lawn, garden, or landscape. However, like any piece of machinery, it can encounter issues that affect its performance and longevity. The importance of addressing these common problems lies in the following:

  • Longevity: By addressing problems promptly and correctly, you can extend the lifespan of your STIHL FS 38. Regular maintenance and problem-solving keep your trimmer in good working condition for years to come.
  • Efficiency: A trimmer that functions without problems ensures efficient yard work. You’ll save time and effort when your trimmer operates as it should.
  • Cost Savings: Preventive maintenance and timely repairs can save you money in the long run. It’s more cost-effective to address minor issues early than to deal with major breakdowns later.
  • User Satisfaction: A well-maintained trimmer not only performs better but also enhances your overall user experience. Enjoying a reliable tool makes yard work more satisfying.

Applying Provided Solutions for Effective Maintenance

We’ve delved into the specifics of addressing five common problems with the STIHL FS 38, from engine starting issues to fuel and carburetor problems. Each solution was carefully crafted to help you maintain your trimmer effectively. Now, it’s your turn to apply these solutions:

  • Engine Starting Solutions: Ensure the right fuel mix and spark plug maintenance for smooth starts.
  • Trimmer Line Maintenance: Follow tips to prevent line breakage and maintain your trimmer line effectively.
  • Preventing Overheating: Implement strategies to prevent overheating and cool your trimmer down when needed.
  • Improving Trimming Performance: Optimize your trimmer’s performance with adjustments, maintenance, and efficient trimming techniques.
  • Fuel and Carburetor Maintenance: Clean and troubleshoot fuel and carburetor issues, following safety precautions and step-by-step guides.

By applying these solutions, you’ll not only overcome common problems but also keep your STIHL FS 38 in top condition, ensuring it remains your reliable companion in maintaining your outdoor spaces.

Reiterating the Relevance of the Focus Keyword “STIHL FS 38”

Throughout this blog post, we’ve consistently emphasized our focus keyword, “STIHL FS 38.” We’ve done this to ensure that you, our readers, can easily find the information you need when seeking solutions and maintenance advice for this specific trimmer model.

By optimizing our content for this keyword, we aim to provide you with the most relevant and comprehensive guidance on maintaining your STIHL FS 38.

In conclusion, addressing common problems and effectively maintaining your STIHL FS 38 trimmer is essential for its longevity, efficiency, and overall satisfaction as a user. We hope this guide has been informative and practical, enabling you to tackle any issues that may arise and ensure your trimmer’s reliable performance.

Whether you’re a homeowner or a professional landscaper, your STIHL FS 38 can continue to be a valuable tool in your arsenal for years to come.

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