Stihl BG56 Blower Carburetor Fixes (Pro Arborist Tips)

Let’s dive into fixing your Stihl BG56 blower carburetor, shall we? But before we get our hands greasy, let’s talk a bit about why this guide matters, especially considering where you might be reading this from.

The Global Landscape of Small Engine Repair and the Mighty Stihl BG56

Whether you’re nestled in the frosty forests of Scandinavia, the sun-baked Australian outback, or the humid woodlands of the American Southeast, one thing remains constant: the need for reliable outdoor power equipment. And Stihl, with its reputation for robust engineering, often finds its way into the hands of both professionals and homeowners alike.

Now, I’ve spent years in the wood processing and forestry world, from felling towering pines in Oregon to meticulously stacking firewood in my own backyard. I’ve seen firsthand how vital a well-maintained blower is. It’s not just about clearing leaves; it’s about maintaining firebreaks, prepping timber sites, and general site cleanliness – all critical for safety and efficiency.

The problem? Carburetors, especially in small engines like the Stihl BG56, are notorious for being finicky. They’re sensitive to fuel quality, air intake, and even changes in altitude. This guide isn’t just about fixing a carburetor; it’s about empowering you to keep your equipment running smoothly, no matter where you are in the world.

According to recent statistics, small engine repair is a booming industry. The global small engine market is projected to reach $38.4 billion by 2027, driven by the increasing demand for outdoor power equipment. However, the cost of professional repairs can be significant, especially in remote areas. That’s why understanding how to troubleshoot and fix common issues like a faulty carburetor is invaluable.

And to make it personal, let me tell you about the time I was contracted to clear a massive debris field after a windstorm in the Pacific Northwest. My Stihl BG56 was my trusty companion. But midway through, it started sputtering and refusing to start. I was miles from the nearest shop, with a looming deadline. That day, I learned the hard way the importance of understanding carburetor basics and carrying a small repair kit. It’s a lesson I want to pass on to you.

Understanding Carburetor Basics: Your BG56’s Heart

Before we grab our tools, let’s define some key concepts. What exactly is a carburetor, and what does it do?

What is a Carburetor?

Simply put, a carburetor is the heart of your Stihl BG56. It’s responsible for mixing air and fuel in the correct proportions to create a combustible mixture that powers the engine. A carburetor regulates the amount of air and fuel entering the engine based on the throttle position, engine speed, and load.

Why Carburetors Fail: Common Culprits

Carburetors are precision instruments, and several factors can cause them to malfunction:

Dirty Fuel: This is the number one culprit. Old or contaminated fuel can clog the tiny passages within the carburetor, restricting fuel flow.
Air Leaks: A loose or cracked intake manifold, damaged gaskets, or a faulty carburetor body can allow air to enter the system, leaning out the fuel mixture.
Sticking Needle Valve: The needle valve regulates fuel flow into the carburetor bowl. If it sticks due to dirt or corrosion, it can cause flooding or fuel starvation.
Diaphragm Issues: Many small engine carburetors use diaphragms to pump fuel. These diaphragms can become brittle and crack over time, affecting fuel delivery.
Improper Adjustment: The carburetor’s idle and high-speed jets need to be properly adjusted for optimal performance. Incorrect settings can lead to poor running or starting issues.

Key Carburetor Components: A Quick Tour

Understanding the main components of your BG56’s carburetor will make troubleshooting much easier:

Carburetor Body: The main housing that contains all the other components.
Fuel Bowl: A reservoir that holds a supply of fuel.
Float: A small plastic or metal device that regulates the fuel level in the bowl.
Needle Valve: Controls the flow of fuel into the bowl based on the float position.
Main Jet: Meters the amount of fuel delivered to the engine at higher speeds.
Idle Jet: Meters the amount of fuel delivered to the engine at idle.
Throttle Valve: Controls the amount of air entering the engine.
Choke Valve: Restricts airflow to richen the fuel mixture for cold starting.
Diaphragm(s): Pumps fuel from the fuel tank to the carburetor (on some models).

Diagnosing the Problem: Is it Really the Carburetor?

Before tearing into your carburetor, let’s make sure that’s actually where the problem lies. A little detective work can save you a lot of time and frustration.

Common Symptoms of a Carburetor Problem

Here are some telltale signs that your Stihl BG56’s carburetor might be acting up:

Difficulty Starting: The engine cranks but refuses to start, or starts only with difficulty.
Rough Idling: The engine idles unevenly, stalls frequently, or runs very roughly.
Poor Performance: The engine lacks power, hesitates when accelerating, or bogs down under load.
Flooding: The engine floods with fuel, making it difficult or impossible to start. You might smell a strong gasoline odor.
Backfiring: The engine backfires or pops, indicating an improper air-fuel mixture.
Excessive Smoke: The engine produces excessive black or white smoke, indicating a rich or lean fuel mixture.

Ruling Out Other Potential Issues

Before blaming the carburetor, rule out these other common problems:

Fuel Issues:
- Old Fuel: Is your fuel fresh? Gasoline degrades over time, especially when mixed with ethanol. Drain the old fuel and replace it with fresh fuel. I always recommend using fuel stabilizer, especially if you don’t use the blower regularly.
- Contaminated Fuel: Check for water or debris in the fuel tank. Drain and clean the tank if necessary.
- Fuel Line Problems: Inspect the fuel lines for cracks, leaks, or kinks. Replace any damaged lines.
- Fuel Filter: A clogged fuel filter can restrict fuel flow. Replace the fuel filter.
Spark Issues:
- Spark Plug: A fouled or damaged spark plug can prevent the engine from starting. Remove the spark plug and inspect it. Clean or replace it as needed. The spark plug should have a strong, blue spark.
- Ignition Coil: A faulty ignition coil can produce a weak or no spark. Test the ignition coil with a multimeter, or take it to a small engine repair shop for testing.
Air Filter: A clogged air filter can restrict airflow to the engine, leading to poor performance. Clean or replace the air filter.
Exhaust System: A clogged exhaust system can restrict exhaust flow, leading to poor performance. Check the exhaust port and muffler for obstructions.

The Compression Test: A Vital Step

Before you get too deep into carburetor work, perform a compression test. Low compression can mimic carburetor problems, and fixing the carburetor won’t solve the underlying issue.

A compression test measures the pressure inside the engine cylinder. Low compression indicates worn piston rings, damaged valves, or a blown head gasket.

You’ll need a compression tester for this. Here’s how to do it:

Warm up the engine (if possible).
Remove the spark plug.
Screw the compression tester into the spark plug hole.
Crank the engine several times with the throttle wide open.
Note the highest reading on the compression tester.

Interpreting the Results:

Good Compression: A reading of 100 PSI or higher is generally considered good.
Low Compression: A reading below 80 PSI indicates a problem with the engine’s internal components.
Significant Variation: If the compression readings vary significantly between cylinders (on a multi-cylinder engine), it indicates a problem with one or more cylinders.

If you find low compression, you’ll need to address that issue before tackling the carburetor.

Tools and Materials: Preparing for Success

Before we start wrenching, let’s gather the necessary tools and materials. Having everything on hand will make the job much smoother.

Essential Tools

Screwdrivers: You’ll need both flathead and Phillips head screwdrivers in various sizes. A small, precision screwdriver set is also helpful for adjusting the carburetor jets.
Pliers: A pair of needle-nose pliers and a pair of standard pliers will come in handy for various tasks.
Wrenches: A set of open-end wrenches or an adjustable wrench will be needed for removing the carburetor.
Carburetor Cleaner: This is essential for cleaning the carburetor’s internal passages. Make sure to use a cleaner that is safe for plastic and rubber components.
Compressed Air: A can of compressed air is useful for blowing out debris from the carburetor.
Carburetor Adjustment Tool: Some Stihl carburetors require a special tool for adjusting the jets.
Spark Plug Wrench: For removing and installing the spark plug.
Clean Rags: For wiping up spills and cleaning parts.
Small Brush: A small brush, like a toothbrush, is helpful for scrubbing the carburetor.
Safety Glasses: Protect your eyes from flying debris and chemicals.
Gloves: Protect your hands from dirt and chemicals.

Optional but Recommended Tools

Ultrasonic Cleaner: An ultrasonic cleaner is a great investment if you frequently work on carburetors. It uses sound waves to dislodge dirt and grime from the carburetor’s internal passages.
Carburetor Synchronizer: If you’re working on a multi-cylinder engine, a carburetor synchronizer can help you ensure that all the carburetors are properly balanced.
Multimeter: A multimeter can be used to test the ignition coil and other electrical components.
Compression Tester: As mentioned earlier, a compression tester is essential for diagnosing engine problems.

Consumable Materials

Carburetor Rebuild Kit: This kit contains all the necessary gaskets, O-rings, and diaphragms for rebuilding the carburetor.
Fuel Filter: Replace the fuel filter whenever you service the carburetor.
Fuel Line: Replace any cracked or damaged fuel lines.
Spark Plug: Replace the spark plug if it’s fouled or damaged.
Fuel Stabilizer: Add fuel stabilizer to your gasoline to prevent it from degrading.
Grease: A small amount of grease can be used to lubricate the carburetor linkages.

Budgeting for the Repair

The cost of repairing your Stihl BG56 carburetor can vary depending on the parts you need to replace and whether you choose to do the repair yourself or take it to a professional.

Here’s a rough breakdown of the costs:

Carburetor Rebuild Kit: $10 – $30
Fuel Filter: $5 – $10
Fuel Line: $5 – $10
Spark Plug: $5 – $10
Carburetor Cleaner: $5 – $10
Professional Repair: $50 – $150

Doing the repair yourself can save you a significant amount of money, but it requires some mechanical skill and patience.

Step-by-Step Guide: Carburetor Removal and Disassembly

Alright, let’s get down to business. Here’s a detailed, step-by-step guide to removing and disassembling the carburetor on your Stihl BG56 blower.

Step 1: Safety First!

Disconnect the Spark Plug: This is crucial to prevent accidental starting. Pull the spark plug wire off the spark plug.
Work in a Well-Ventilated Area: Gasoline fumes are flammable and harmful. Work outdoors or in a well-ventilated garage.
Wear Safety Glasses and Gloves: Protect your eyes and hands from fuel and chemicals.

Step 2: Accessing the Carburetor

The exact steps for accessing the carburetor may vary slightly depending on your specific BG56 model, but here’s a general guide:

Remove the Air Filter Cover: Locate the air filter cover, usually on the side of the engine. Remove the screws or clips holding it in place.
Remove the Air Filter: Carefully remove the air filter. Inspect it and clean or replace it if necessary.
Disconnect the Fuel Lines: Locate the fuel lines connected to the carburetor. Use pliers to gently disconnect them. Be prepared for some fuel to spill, so have a rag handy. Make a note of which line goes where, or take a picture for reference.
Disconnect the Throttle Linkage: Locate the throttle linkage connected to the carburetor. Disconnect it carefully, noting how it’s attached.
Remove the Carburetor Mounting Bolts: Locate the bolts or screws that hold the carburetor to the engine. Remove them carefully.
Remove the Carburetor: Gently pull the carburetor away from the engine.

Step 3: Carburetor Disassembly

Now that you have the carburetor removed, it’s time to disassemble it. Work on a clean surface and keep track of all the small parts.

Remove the Fuel Bowl: The fuel bowl is usually held in place by a screw or bolt. Remove the screw or bolt and carefully remove the fuel bowl.
Remove the Float and Needle Valve: The float is a small plastic or metal device that regulates the fuel level in the bowl. Carefully remove the float and needle valve. Pay attention to how they are oriented.
Remove the Jets: Locate the main jet and idle jet. These are usually small brass screws or plugs. Use a small screwdriver to carefully remove them.
Remove the Diaphragm(s): Some carburetors have diaphragms that pump fuel. If your carburetor has diaphragms, carefully remove them. Note their orientation.
Remove Any Other Components: Remove any other removable components, such as O-rings or gaskets.

Step 4: Cleaning the Carburetor

Now that the carburetor is disassembled, it’s time to clean it.

Spray with Carburetor Cleaner: Spray all the carburetor components with carburetor cleaner. Pay special attention to the small passages and jets.
Soak the Components: Let the components soak in carburetor cleaner for at least 30 minutes.
Scrub the Components: Use a small brush to scrub the components, removing any remaining dirt or grime.
Blow Out with Compressed Air: Use compressed air to blow out all the passages and jets. Make sure to wear safety glasses to protect your eyes.
Inspect the Components: Inspect all the components for damage or wear. Replace any damaged components with new ones.

Step-by-Step Guide: Carburetor Reassembly and Installation

Now that the carburetor is clean and inspected, it’s time to reassemble it and install it back on the engine.

Step 1: Reassembling the Carburetor

Install the Jets: Install the main jet and idle jet. Make sure they are tightened securely.
Install the Diaphragm(s): If your carburetor has diaphragms, install them carefully. Make sure they are oriented correctly.
Install the Float and Needle Valve: Install the float and needle valve. Make sure the float moves freely.
Install the Fuel Bowl: Install the fuel bowl. Make sure the screw or bolt is tightened securely.
Install Any Other Components: Install any other components, such as O-rings or gaskets.

Step 2: Installing the Carburetor

Mount the Carburetor: Position the carburetor on the engine and install the mounting bolts or screws. Tighten them securely.
Connect the Throttle Linkage: Connect the throttle linkage to the carburetor. Make sure it’s properly adjusted.
Connect the Fuel Lines: Connect the fuel lines to the carburetor. Make sure they are securely attached and that they are connected to the correct ports.
Install the Air Filter: Install the air filter.
Install the Air Filter Cover: Install the air filter cover.

Step 3: Final Checks

Check for Leaks: After installing the carburetor, check for fuel leaks. If you find any leaks, tighten the connections or replace the fuel lines.
Adjust the Carburetor: Adjust the carburetor’s idle and high-speed jets for optimal performance. See the next section for instructions.
Connect the Spark Plug: Connect the spark plug wire to the spark plug.

Carburetor Adjustment: Fine-Tuning for Peak Performance

Carburetor adjustment is crucial for ensuring that your Stihl BG56 runs smoothly and efficiently.

Identifying Adjustment Screws

Most Stihl BG56 carburetors have two adjustment screws:

Idle Speed Screw (T): This screw controls the engine’s idle speed.
High-Speed Jet (H) and Low-Speed Jet (L): These screws control the fuel mixture at high and low speeds.

The Importance of Proper Adjustment

Proper carburetor adjustment is vital for:

Optimal Performance: A properly adjusted carburetor ensures that the engine runs smoothly and efficiently.
Fuel Efficiency: A properly adjusted carburetor can improve fuel efficiency.
Engine Longevity: A properly adjusted carburetor can help extend the life of your engine.

Adjustment Procedure

Important Note: Carburetor adjustment can be tricky, and it’s easy to damage your engine if you don’t do it correctly. If you’re not comfortable adjusting the carburetor yourself, take it to a professional. Some carburetors will need a special tool to adjust the high and low speed screws.

Warm Up the Engine: Start the engine and let it warm up for a few minutes.
Adjust the Idle Speed: Turn the idle speed screw (T) until the engine idles smoothly without stalling.
Adjust the Low-Speed Jet: Turn the low-speed jet (L) until the engine accelerates smoothly from idle without hesitating or bogging down.
Adjust the High-Speed Jet: Turn the high-speed jet (H) until the engine runs smoothly at full throttle without surging or cutting out.
Fine-Tune the Adjustments: Make small adjustments to the jets until you achieve the best possible performance.

Tips for Adjustment:

Start Rich: It’s better to start with a slightly rich fuel mixture (turning the screws counter-clockwise) and then lean it out gradually.
Listen to the Engine: Pay attention to how the engine sounds. A properly adjusted engine will run smoothly and efficiently.
Use a Tachometer: A tachometer can help you accurately set the idle speed.

Troubleshooting Common Carburetor Problems: A Practical Guide

Even after cleaning and adjusting your carburetor, you might still encounter problems. Here are some common issues and how to troubleshoot them.

Engine Won’t Start

No Fuel: Check the fuel tank, fuel lines, and fuel filter. Make sure there is fuel in the tank and that the fuel lines are not clogged or kinked.
No Spark: Check the spark plug. Make sure it’s clean and properly gapped. Test the ignition coil with a multimeter.
Flooded Engine: If the engine is flooded, remove the spark plug and crank the engine to clear the excess fuel.
Low Compression: Perform a compression test. Low compression indicates a problem with the engine’s internal components.

Engine Runs Rough

Dirty Carburetor: The carburetor may still be dirty. Disassemble and clean it again.
Air Leak: Check for air leaks around the intake manifold and carburetor.
Improper Adjustment: Adjust the carburetor’s idle and high-speed jets.

Engine Stalls

Idle Speed Too Low: Increase the idle speed.
Dirty Carburetor: The carburetor may be dirty. Disassemble and clean it again.
Air Leak: Check for air leaks around the intake manifold and carburetor.

Engine Lacks Power

Clogged Air Filter: Clean or replace the air filter.
Dirty Carburetor: The carburetor may be dirty. Disassemble and clean it again.
Improper Adjustment: Adjust the carburetor’s idle and high-speed jets.

Engine Backfires

Lean Fuel Mixture: Adjust the carburetor to richen the fuel mixture.
Ignition Timing: Check the ignition timing.
Valve Problems: Check the valves for proper seating and operation.

Pro Arborist Tips: Beyond the Basics

Now, let’s dive into some insider tips that I’ve picked up over the years. These aren’t in any manual, but they can make a big difference in your success.

Fuel Stabilization: A Must-Do

I can’t stress this enough: fuel stabilizer is your best friend. Ethanol-blended gasoline is notorious for attracting moisture and breaking down over time, leading to gum and varnish buildup in the carburetor. Always add a fuel stabilizer to your gasoline, especially if you don’t use your blower regularly.

The Importance of Fresh Fuel

Don’t let fuel sit in your blower for extended periods, especially over the winter. Drain the fuel tank and run the engine until it stalls to ensure that the carburetor is empty.

Regular Maintenance: Prevention is Key

Regular maintenance is the key to preventing carburetor problems. Clean the air filter regularly, replace the fuel filter annually, and use fresh fuel.

Carrying a Carburetor Rebuild Kit

If you rely on your Stihl BG56 for professional work, consider carrying a carburetor rebuild kit with you. It can be a lifesaver if you experience carburetor problems in the field.

The Ultrasonic Cleaner: A Game Changer

As I mentioned earlier, an ultrasonic cleaner is a fantastic tool for cleaning carburetors. It uses sound waves to dislodge dirt and grime from the carburetor’s internal passages, making it much more effective than manual cleaning.

Understanding Altitude Adjustments

If you live or work at high altitudes, you may need to adjust your carburetor to compensate for the thinner air. Consult your Stihl BG56 owner’s manual for instructions on altitude adjustments.

Case Studies: Real-World Examples

Let’s look at a couple of real-world case studies to illustrate the importance of proper carburetor maintenance and repair.

Case Study 1: The Neglected Blower

A landscaping company in Florida had a fleet of Stihl BG56 blowers. They were experiencing frequent carburetor problems, leading to downtime and increased repair costs. After analyzing their maintenance practices, it became clear that they were neglecting basic maintenance tasks, such as cleaning the air filters and using fresh fuel. They implemented a regular maintenance schedule and started using fuel stabilizer. As a result, their carburetor problems decreased significantly, and their equipment uptime improved.

Case Study 2: The High-Altitude Arborist

An arborist working in the Rocky Mountains was experiencing poor performance from his Stihl BG56 blower. He had cleaned and adjusted the carburetor, but the engine still lacked power. After consulting his owner’s manual, he realized that he needed to adjust the carburetor for high altitude. He made the necessary adjustments, and the engine’s performance improved dramatically.

Next Steps and Additional Resources

Congratulations! You’ve successfully diagnosed, cleaned, and potentially rebuilt your Stihl BG56 blower carburetor. Here are some next steps and additional resources to help you keep your equipment running smoothly.

Regular Maintenance Schedule

Daily: Check fuel level, air filter condition.
Weekly: Clean air filter, inspect fuel lines.
Monthly: Replace fuel filter, check spark plug.
Annually: Rebuild carburetor (if needed).

Where to Find Parts and Supplies

Stihl Dealers: Your local Stihl dealer is a great source for parts, supplies, and technical advice.
Online Retailers: Online retailers like Amazon, eBay, and HL Supply offer a wide variety of parts and supplies for Stihl equipment.
Small Engine Repair Shops: Your local small engine repair shop can provide parts, service, and advice.

Additional Resources

Stihl Owner’s Manual: Your Stihl BG56 owner’s manual contains valuable information about maintenance, troubleshooting, and repair.
Online Forums: Online forums like ArboristSite and LawnSite are great places to ask questions and get advice from other Stihl owners.
YouTube: YouTube is a great resource for finding videos on carburetor repair and maintenance.

Final Thoughts

Fixing your Stihl BG56 blower carburetor might seem daunting at first, but with the right knowledge, tools, and a little patience, it’s a task you can definitely tackle yourself. Remember, regular maintenance and attention to detail are key to keeping your equipment running smoothly for years to come. And now, armed with this guide, you’re well-equipped to keep your Stihl BG56 roaring to life, no matter where your wood processing adventures take you. Happy blowing!