Stihl FS55 Ignition Coil Guide (5 Expert Tips for Smooth Starts)
Ah, there’s nothing quite like the warmth of a crackling fire on a chilly evening, is there? It’s a primal connection, a dance between the elements that soothes the soul. But that warmth, that comfort, starts long before the match is struck. It begins with the satisfying thrum of a well-maintained engine, the bite of a saw chain, and the methodical process of transforming raw timber into usable firewood. And at the heart of that process, often overlooked but absolutely critical, is the ignition coil.
So, whether you’re a seasoned pro or a weekend warrior just starting to explore the world of wood processing, this guide is for you. I’ll share my expert tips, learned through trial and error, to help you diagnose, troubleshoot, and maintain your Stihl FS55 ignition coil for smooth, reliable starts every time. Let’s get started!
Stihl FS55 Ignition Coil Guide: 5 Expert Tips for Smooth Starts
The user intent behind the search query “Stihl FS55 Ignition Coil Guide (5 Expert Tips for Smooth Starts)” is clear: the user is experiencing starting problems with their Stihl FS55 equipment (likely a string trimmer or brushcutter) and suspects the ignition coil is the issue. They are seeking practical advice and troubleshooting tips to resolve the problem and ensure their equipment starts reliably. They are looking for expert guidance, specifically five key tips, to address the ignition coil and achieve smooth starts.
Understanding the Ignition Coil: The Heart of the Spark
Before diving into troubleshooting and tips, let’s understand what an ignition coil actually does. In simple terms, it’s a transformer. It takes the low-voltage electricity from the engine’s magneto and converts it into the high-voltage spark needed to ignite the fuel-air mixture in the cylinder. Without a healthy spark, your engine is just a collection of metal parts sitting idle.
Think of it like this: you’re trying to light a campfire. The ignition coil is like the dry tinder that catches the initial spark from your lighter and ignites the larger kindling. If the tinder is damp or missing, you won’t get a fire, no matter how good your lighter is. Similarly, a weak or faulty ignition coil won’t produce a strong enough spark to start your engine, even if everything else is in perfect working order.
Data Point: A typical ignition coil for a small engine like the Stihl FS55 can produce anywhere from 15,000 to 30,000 volts.
Tip #1: The Visual Inspection – Spotting the Obvious
This might seem basic, but it’s surprising how often a simple visual inspection can reveal the problem. Before you even think about busting out the multimeter, take a close look at the ignition coil.
- Cracks and Damage: Look for any visible cracks, chips, or other damage to the coil’s housing. These can indicate physical stress or overheating, both of which can compromise its performance.
- Corrosion: Check the terminals where the wires connect to the coil. Corrosion can build up over time, creating resistance and preventing a good electrical connection.
- Loose Wires: Make sure all the wires connected to the ignition coil are securely attached. A loose wire can cause intermittent starting problems or a complete failure to start.
- Burn Marks: Look for any signs of burning or melting on the coil or its surrounding components. This is a clear indication of a serious problem, often caused by a short circuit.
Personal Story: I once spent hours troubleshooting a stubborn chainsaw that refused to start. I checked the fuel, the spark plug, the carburetor – everything! Finally, in desperation, I took a closer look at the ignition coil and discovered a tiny hairline crack that I had missed before. Replacing the coil solved the problem instantly. It taught me the importance of a thorough visual inspection.
Tip #2: The Spark Plug Test – Confirming the Spark
The spark plug is the final destination for the high-voltage electricity produced by the ignition coil. Testing the spark plug is a quick and easy way to confirm whether the coil is producing a spark.
- Remove the Spark Plug: Carefully remove the spark plug from the engine. Use the correct size spark plug wrench to avoid damaging the plug or the cylinder head.
- Reattach the Spark Plug Wire: Reattach the spark plug wire to the spark plug.
- Ground the Spark Plug: Hold the spark plug against a metal part of the engine block. This provides a ground for the electrical circuit.
- Pull the Starter Rope: Pull the starter rope briskly. You should see a strong, blue spark jumping across the spark plug gap.
If you see a weak, yellow spark or no spark at all, the ignition coil is likely the problem. However, before condemning the coil, it’s worth trying a new spark plug to rule out a faulty plug as the cause.
Caution: When performing this test, be careful not to touch the spark plug or the spark plug wire while pulling the starter rope. The high voltage can give you a nasty shock.
Data Point: A healthy spark should be bright blue and consistent. A weak or intermittent spark indicates a problem with the ignition system, including the coil.
Tip #3: The Air Gap Adjustment – Ensuring Proper Magnetic Induction
The air gap is the distance between the ignition coil and the flywheel. This gap is crucial for proper magnetic induction. When the flywheel rotates, its magnets pass by the ignition coil, inducing a voltage in the coil. If the air gap is too large, the magnetic field will be too weak to induce enough voltage, resulting in a weak or non-existent spark. If the air gap is too small, the coil can rub against the flywheel, causing damage.
- Locate the Air Gap: The air gap is typically located between the ignition coil and the flywheel, near the magnets on the flywheel.
- Loosen the Mounting Bolts: Loosen the bolts that hold the ignition coil in place.
- Use a Feeler Gauge: Use a feeler gauge to set the air gap to the manufacturer’s specifications. A common air gap setting for small engines like the Stihl FS55 is 0.010 to 0.014 inches (0.25 to 0.35 mm).
- Tighten the Mounting Bolts: Once the air gap is set correctly, tighten the mounting bolts securely.
Unique Insight: I’ve found that using a business card or a piece of thin cardboard can be a handy substitute for a feeler gauge in a pinch. Just fold the card in half to get the desired thickness.
Case Study: I once worked on a Stihl FS55 that was consistently hard to start. The spark plug was good, and the ignition coil seemed to be working, but the engine just wouldn’t fire up reliably. After checking everything else, I decided to double-check the air gap. It turned out that the air gap was significantly too large, preventing the coil from generating a strong enough spark. Adjusting the air gap to the correct setting solved the problem immediately.
Tip #4: The Multimeter Test – Measuring Resistance and Continuity
A multimeter is an invaluable tool for diagnosing electrical problems. It can be used to measure the resistance of the ignition coil and check for continuity in the wiring.
- Resistance Test: Set the multimeter to the ohms setting (Ω). Disconnect the wires from the ignition coil. Touch the multimeter probes to the terminals of the ignition coil. The multimeter should display a resistance reading within the manufacturer’s specifications. A very high or very low resistance reading indicates a faulty coil.
- Continuity Test: Set the multimeter to the continuity setting (usually indicated by a diode symbol or a sound wave symbol). Touch the multimeter probes to the terminals of the ignition coil. The multimeter should beep or display a low resistance reading, indicating that the circuit is complete. If the multimeter doesn’t beep or displays a high resistance reading, the circuit is broken, indicating a faulty coil.
Important Note: Refer to the Stihl FS55 service manual for the specific resistance and continuity values for the ignition coil. These values can vary depending on the model and year of manufacture.
Data Point: The primary coil resistance is typically very low, often less than 1 ohm. The secondary coil resistance, which is the high-voltage side of the coil, is typically much higher, ranging from several thousand to tens of thousands of ohms.
Tip #5: The Wiring and Connections – Tracing the Path of Electricity
Even if the ignition coil itself is in good working order, problems with the wiring and connections can prevent it from functioning properly.
- Inspect the Wiring: Carefully inspect all the wires connected to the ignition coil for any signs of damage, such as cuts, abrasions, or corrosion.
- Check the Connectors: Make sure all the connectors are clean and securely attached. Use a wire brush or sandpaper to clean any corroded connectors.
- Test for Continuity: Use a multimeter to test the continuity of the wiring. Disconnect the wires from the ignition coil and the engine. Touch the multimeter probes to the ends of the wires. The multimeter should beep or display a low resistance reading, indicating that the circuit is complete.
- Look for Shorts to Ground: Use a multimeter to check for shorts to ground. Disconnect the wires from the ignition coil and the engine. Touch one multimeter probe to the wire and the other probe to a metal part of the engine block. The multimeter should not beep or display a low resistance reading. If it does, the wire is shorted to ground.
Personal Story: I once spent an entire afternoon chasing a ghost in a chainsaw’s electrical system. The engine would start and run for a few minutes, then suddenly die. I replaced the ignition coil, the spark plug, and even the carburetor, but the problem persisted. Finally, I decided to meticulously trace every wire in the system. I discovered a tiny, almost invisible abrasion on one of the wires that was causing it to intermittently short to ground. Repairing the wire solved the problem instantly. It was a frustrating experience, but it taught me the importance of paying attention to the details.
Advanced Troubleshooting: When the Basics Aren’t Enough
Sometimes, even after performing all the basic troubleshooting steps, the problem remains elusive. In these cases, it’s time to delve into some more advanced techniques.
- The Condenser Test: The condenser (also known as a capacitor) is a small electronic component that is often located near the ignition coil. Its purpose is to store electrical energy and release it to the coil at the precise moment needed to create a spark. A faulty condenser can cause weak spark, misfires, or a complete failure to start. Testing a condenser requires a special capacitor tester, which can be purchased at most auto parts stores.
- The Flywheel Magnet Test: The flywheel magnets are responsible for inducing a voltage in the ignition coil. If the magnets are weak or damaged, they may not be able to generate enough voltage to produce a strong spark. Testing the flywheel magnets requires a special gauss meter, which measures the strength of the magnetic field.
- The Crankshaft Position Sensor Test: Some newer engines are equipped with a crankshaft position sensor, which provides information to the ignition system about the position of the crankshaft. A faulty crankshaft position sensor can cause timing problems, misfires, or a complete failure to start. Testing a crankshaft position sensor requires a special diagnostic tool.
Important Note: These advanced troubleshooting techniques require specialized tools and knowledge. If you are not comfortable performing these tests yourself, it’s best to take your equipment to a qualified service technician.
Prevention is Key: Maintaining Your Ignition Coil for Longevity
The best way to avoid ignition coil problems is to prevent them from happening in the first place. Here are some tips for maintaining your ignition coil and ensuring its longevity:
- Keep the Engine Clean: Dirt and debris can accumulate around the ignition coil, trapping heat and causing it to overheat. Regularly clean the engine with a brush and compressed air to remove any dirt or debris.
- Avoid Overheating: Overheating is a common cause of ignition coil failure. Avoid running the engine at high speeds for extended periods of time. Make sure the engine’s cooling system is functioning properly.
- Use the Correct Fuel and Oil: Using the wrong fuel or oil can damage the engine and cause the ignition coil to overheat. Always use the fuel and oil recommended by the manufacturer.
- Store the Equipment Properly: When storing the equipment for extended periods of time, drain the fuel tank and run the engine until it stalls. This will prevent the fuel from gumming up the carburetor and causing starting problems. Store the equipment in a dry, well-ventilated place.
- Regularly Inspect the Ignition System: Regularly inspect the ignition system for any signs of damage or wear. Check the spark plug, the wiring, and the ignition coil itself. Replace any worn or damaged components promptly.
Data Point: Studies have shown that proper maintenance can extend the lifespan of an ignition coil by as much as 50%.
Choosing a Replacement Ignition Coil: Quality Matters
If you determine that your ignition coil is faulty and needs to be replaced, it’s important to choose a high-quality replacement. There are many aftermarket ignition coils available, but not all of them are created equal.
- Stick with OEM: Whenever possible, stick with original equipment manufacturer (OEM) parts. OEM ignition coils are designed specifically for your engine and are more likely to provide reliable performance.
- Check Reviews: Before purchasing an aftermarket ignition coil, check online reviews to see what other users have to say about its performance and reliability.
- Consider the Warranty: Choose an ignition coil that comes with a warranty. This will protect you in case the coil fails prematurely.
- Compare Prices: Compare prices from different vendors to ensure you are getting the best deal. However, don’t sacrifice quality for price. A cheap ignition coil may save you money in the short term, but it could end up costing you more in the long run.
Unique Insight: I’ve found that investing in a slightly more expensive, reputable brand of ignition coil often pays off in the long run. These coils tend to be more durable and reliable, saving you time and money on repairs down the road.
Firewood Seasoning: The Final Step to Warmth
While this guide focuses on the ignition coil and starting your equipment, it’s important to remember that the ultimate goal is to produce high-quality firewood that burns efficiently and cleanly. Proper firewood seasoning is essential for achieving this goal.
- Split the Wood: Splitting the wood exposes more surface area to the air, allowing it to dry more quickly.
- Stack the Wood Properly: Stack the wood in a single row, with the ends exposed to the air. This allows for good air circulation.
- Elevate the Wood: Elevate the wood off the ground using pallets or other supports. This prevents moisture from wicking up into the wood.
- Cover the Wood: Cover the top of the woodpile with a tarp or other waterproof material. This will protect the wood from rain and snow.
- Allow Adequate Time for Seasoning: Allow the wood to season for at least six months, and preferably longer. The longer the wood seasons, the drier it will become, and the better it will burn.
Data Point: Properly seasoned firewood has a moisture content of 20% or less. Unseasoned firewood can have a moisture content of 50% or more.
Firewood Seasoning Techniques and Safety Considerations:
- Air Drying: This is the most common and cost-effective method. Stacking wood properly allows for natural air circulation, gradually reducing moisture content over several months.
- Safety: Wear gloves and eye protection when handling and stacking wood to prevent splinters and debris from causing injury.
- Kiln Drying: This method uses controlled heat to rapidly dry wood, reducing seasoning time to just a few days. While faster, it’s more expensive and requires specialized equipment.
- Safety: Be cautious around kilns due to high temperatures and potential fire hazards.
- Solar Drying: Utilizing solar energy by constructing a greenhouse-like structure can accelerate drying.
- Safety: Ensure proper ventilation to prevent overheating and moisture buildup.
Project planning and execution:
- Assessment: Evaluate the amount of wood required, available space, and necessary tools (chainsaw, splitter, moisture meter).
- Preparation: Gather tools, clear the stacking area, and ensure proper safety gear is accessible.
- Execution: Cut, split, stack, and cover the wood, monitoring moisture levels regularly.
- Maintenance: Check stacks periodically for stability and proper airflow.
- Storage: Once seasoned, move the wood to a dry storage area, such as a shed or garage.
Conclusion: Keeping the Spark Alive
The Stihl FS55 is a reliable piece of equipment, but like any machine, it requires regular maintenance to keep it running smoothly. By understanding the function of the ignition coil and following these expert tips, you can troubleshoot starting problems and ensure your equipment starts reliably every time.
Remember, the key to success is to be thorough, methodical, and patient. Don’t be afraid to experiment and learn from your mistakes. And most importantly, always prioritize safety.
Now, go forth and conquer that woodpile! And may your fires always burn bright. The warmth of a well-maintained engine and a perfectly seasoned stack of firewood is a reward well worth the effort.
