Husqvarna 440 Won’t Start (5 Pro Fixes Every Arborist Needs)

Ever pulled the starter cord on your Husqvarna 440 chainsaw until you thought your arm would fall off, only to be met with stubborn silence? I know I have. It’s a frustrating experience, especially when you’ve got a pile of logs waiting to be turned into firewood. A chainsaw that won’t start is a common problem, and often the fix is simpler than you might think. As someone who’s spent years felling trees, processing timber, and splitting firewood, I’ve encountered this issue more times than I care to admit. This guide will walk you through five pro fixes that can get your Husqvarna 440 roaring back to life. We’ll cover everything from basic troubleshooting to more advanced techniques, ensuring you have the knowledge to diagnose and resolve the issue.

Husqvarna 440 Won’t Start: 5 Pro Fixes Every Arborist Needs

A chainsaw that refuses to start can throw a wrench into any wood processing operation, whether you’re a seasoned arborist or a weekend warrior preparing firewood. Understanding the common culprits and knowing how to address them is crucial for efficiency and safety. These fixes are designed to be accessible to beginners while offering insights that even experienced users might find valuable.

1. Fuel System Check: The Lifeline of Your Chainsaw

The fuel system is the heart of your chainsaw. Without a proper supply of clean fuel, your Husqvarna 440 is going nowhere. This is often the first place I check when a saw refuses to start.

1.1. Fuel Mixture: Getting the Ratio Right

The Problem: Chainsaws require a precise mixture of gasoline and 2-stroke oil. Too much oil, and the engine struggles to ignite. Too little, and you risk severe engine damage. Husqvarna typically recommends a 50:1 ratio (50 parts gasoline to 1 part 2-stroke oil) for their chainsaws. Using the wrong fuel mixture is a very common mistake.
My Experience: I once had a batch of firewood I needed to get through before winter. My chainsaw wouldn’t start. It turned out I had inadvertently mixed a batch of fuel with too much oil. The saw was simply flooded.
The Fix:
1. Drain the Old Fuel: Empty the fuel tank completely. Use a fuel siphon or carefully tip the saw over, ensuring you collect the fuel in a suitable container. Dispose of the old fuel responsibly.
2. Prepare a Fresh Mixture: Use a calibrated measuring container to accurately mix the correct ratio of gasoline and 2-stroke oil. I prefer using a fuel stabilizer as well, especially if the saw will be sitting for extended periods. The stabilizer prevents the fuel from breaking down and gumming up the carburetor.
3. Fuel Type: Use a high-octane fuel (89 or higher) to ensure optimal performance.
4. Refill the Tank: Carefully pour the fresh fuel mixture into the tank.

1.2. Fuel Filter: Ensuring Clean Fuel Flow

The Problem: The fuel filter, located inside the fuel tank, prevents debris from entering the carburetor. A clogged filter restricts fuel flow, leading to starting problems.
My Experience: I was once working on a particularly dusty site, felling trees near a construction zone. My chainsaw started sputtering and eventually died. The fuel filter was completely caked with dirt and sawdust.
The Fix:
1. Locate the Fuel Filter: The fuel filter is usually attached to a fuel line inside the fuel tank. Use a hooked wire or pliers to carefully retrieve it.
2. Inspect the Filter: Examine the filter for any signs of dirt, debris, or damage.
3. Clean or Replace: If the filter is only slightly dirty, you can try cleaning it with carburetor cleaner. However, if it’s heavily clogged or damaged, it’s best to replace it. Fuel filters are inexpensive and readily available.
4. Reinstall the Filter: Attach the new or cleaned filter to the fuel line and carefully place it back into the fuel tank.

1.3. Fuel Lines: Checking for Cracks and Leaks

The Problem: Fuel lines can become brittle and cracked over time, leading to air leaks that disrupt fuel flow.
The Fix:
1. Inspect the Fuel Lines: Carefully examine the fuel lines for any signs of cracks, leaks, or damage. Pay close attention to the areas where the lines connect to the fuel tank, carburetor, and fuel filter.
2. Replace Damaged Lines: If you find any damaged fuel lines, replace them immediately. Use fuel lines specifically designed for chainsaws, as they are resistant to fuel and oil.
3. Ensure Proper Connections: Make sure all fuel line connections are secure and airtight. Use fuel line clamps if necessary.

2. Spark Plug Inspection: Igniting the Fire

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

2.1. Spark Plug Condition: Reading the Signs

The Problem: A spark plug can become fouled with carbon deposits, oil, or fuel, preventing it from producing a strong spark.
My Experience: I once had a chainsaw that would start intermittently. Sometimes it would fire right up, other times it would refuse to start. The spark plug looked black and oily.
The Fix:
1. Locate the Spark Plug: The spark plug is usually located on the side of the engine, near the cylinder head.
2. Remove the Spark Plug: Use a spark plug wrench to carefully remove the spark plug.
3. Inspect the Spark Plug: Examine the spark plug for any signs of damage, wear, or fouling. A healthy spark plug should have a clean, dry electrode.
4. Clean or Replace: If the spark plug is only slightly fouled, you can try cleaning it with a wire brush or spark plug cleaner. However, if it’s heavily fouled, cracked, or damaged, it’s best to replace it.
5. Spark Plug Gap: Ensure the spark plug gap is set to the manufacturer’s specifications (usually around 0.020 inches or 0.5 mm). Use a spark plug gap tool to adjust the gap if necessary.
6. Reinstall the Spark Plug: Carefully reinstall the spark plug and tighten it to the specified torque.

2.2. Spark Test: Ensuring a Strong Spark

The Problem: Even if the spark plug looks clean, it may not be producing a strong enough spark to ignite the fuel mixture.
The Fix:
1. Connect the Spark Plug Wire: Reconnect the spark plug wire to the spark plug.
2. Ground the Spark Plug: Hold the spark plug against a metal part of the engine (e.g., the cylinder head) to ground it.
3. Pull the Starter Cord: Pull the starter cord and observe the spark plug. You should see a strong, blue spark jumping across the electrode gap.
4. No Spark: If you don’t see a spark, or if the spark is weak or intermittent, the spark plug is likely faulty and needs to be replaced. It could also indicate a problem with the ignition coil.

3. Carburetor Issues: Mastering the Fuel-Air Mix

The carburetor is responsible for mixing fuel and air in the correct proportions for combustion. A dirty or improperly adjusted carburetor can cause a variety of starting and running problems.

3.1. Carburetor Cleaning: Removing Obstructions

The Problem: Over time, the carburetor can become clogged with dirt, varnish, and fuel deposits, restricting fuel flow and disrupting the fuel-air mixture.
My Experience: I once bought a used chainsaw at an auction. It looked to be in good condition, but it wouldn’t start. After some investigation, I discovered that the carburetor was completely gummed up with old fuel.
The Fix:
1. Remove the Air Filter: Remove the air filter to access the carburetor.
2. Spray Carburetor Cleaner: Spray carburetor cleaner into the carburetor throat and any visible passages.
3. Disassemble the Carburetor (Optional): For a thorough cleaning, you can disassemble the carburetor. However, this requires some mechanical skill and knowledge. Take pictures or make notes as you disassemble the carburetor to ensure you can reassemble it correctly.
4. Clean Individual Components: Clean each carburetor component with carburetor cleaner and a soft brush. Pay close attention to the jets and passages.
5. Reassemble the Carburetor: Reassemble the carburetor carefully, following your notes or pictures.
6. Reinstall the Carburetor: Reinstall the carburetor and air filter.

3.2. Carburetor Adjustment: Fine-Tuning the Mixture

The Problem: The carburetor has adjustment screws that control the fuel-air mixture. If these screws are improperly adjusted, the engine may not start or run properly.
The Fix:
1. Locate the Adjustment Screws: The carburetor typically has two or three adjustment screws:
  - L (Low-Speed): Controls the fuel-air mixture at idle and low speeds.
  - H (High-Speed): Controls the fuel-air mixture at high speeds.
  - LA (Idle Speed): Controls the engine’s idle speed.
2. Initial Settings: Start by setting the adjustment screws to the manufacturer’s recommended settings. These settings are usually listed in the chainsaw’s owner’s manual. As a general rule of thumb, start by turning both the L and H screws all the way in (clockwise) and then backing them out 1 to 1.5 turns.
3. Adjust the Low-Speed Screw (L): Start the engine and let it warm up. Turn the L screw slowly until the engine idles smoothly. If the engine stalls or hesitates when you accelerate, turn the L screw out slightly. If the engine idles too fast, turn the L screw in slightly.
4. Adjust the High-Speed Screw (H): After the engine has warmed up, make a test cut in a piece of wood. Turn the H screw slowly until the engine runs smoothly at full throttle. If the engine sounds strained or bogs down, turn the H screw out slightly. If the engine runs too fast or sounds like it’s “screaming,” turn the H screw in slightly. Caution: Running the engine too lean (H screw turned in too far) can cause serious engine damage.
5. Adjust the Idle Speed Screw (LA): Adjust the LA screw until the engine idles smoothly without the chain moving.

3.3. Primer Bulb: Priming the Pump

The Problem: The primer bulb is a small rubber bulb that pumps fuel from the fuel tank to the carburetor, making it easier to start the engine. A cracked or damaged primer bulb can leak air, preventing it from priming the carburetor.
The Fix:
1. Inspect the Primer Bulb: Examine the primer bulb for any signs of cracks, leaks, or damage.
2. Replace the Primer Bulb: If the primer bulb is damaged, replace it immediately. Primer bulbs are inexpensive and easy to replace. Simply remove the old bulb and press the new bulb into place.

4. Compression Test: Gauging Engine Health

Compression is the measure of how tightly the piston seals against the cylinder walls. Low compression indicates wear or damage to the piston rings, cylinder, or valves, making it difficult for the engine to start.

4.1. Performing a Compression Test

The Problem: Low compression means the engine can’t effectively compress the air-fuel mixture, making it difficult to ignite.
The Fix:
1. Remove the Spark Plug: Remove the spark plug from the cylinder head.
2. Insert the Compression Tester: Screw the compression tester into the spark plug hole.
3. Pull the Starter Cord: Pull the starter cord several times while observing the compression tester gauge.
4. Read the Compression: Note the highest reading on the compression tester gauge. A healthy Husqvarna 440 should have a compression reading of at least 120 PSI.
5. Low Compression: If the compression reading is below 120 PSI, it indicates a problem with the engine’s compression. This could be due to worn piston rings, a damaged cylinder, or leaky valves. In this case, it’s best to take the chainsaw to a qualified repair shop for further diagnosis and repair.

4.2. What Low Compression Means

Worn Piston Rings: The piston rings seal the piston against the cylinder walls. Over time, they can wear down, allowing compression to escape.
Damaged Cylinder: The cylinder walls can become scored or damaged, preventing the piston rings from sealing properly.
Leaky Valves: If your chainsaw has valves (some older models do), they can become worn or damaged, allowing compression to escape.

5. Ignition System: Ensuring a Reliable Spark

The ignition system is responsible for generating the high-voltage spark that ignites the fuel mixture in the engine. A faulty ignition coil can prevent the engine from starting.

5.1. Testing the Ignition Coil

The Problem: The ignition coil provides the high-voltage spark to the spark plug. If it’s faulty, no spark will be produced.
The Fix:
1. Disconnect the Spark Plug Wire: Disconnect the spark plug wire from the spark plug.
2. Use a Spark Tester: Insert a spark tester between the spark plug wire and the spark plug.
3. Pull the Starter Cord: Pull the starter cord and observe the spark tester. You should see a strong, blue spark jumping across the gap in the spark tester.
4. No Spark: If you don’t see a spark, or if the spark is weak or intermittent, the ignition coil is likely faulty and needs to be replaced.
5. Multimeter Test (Advanced): You can also test the ignition coil with a multimeter. Consult your chainsaw’s service manual for the specific testing procedure and resistance values.

5.2. Replacing the Ignition Coil

The Fix:
1. Locate the Ignition Coil: The ignition coil is usually located near the flywheel.
2. Disconnect the Wires: Disconnect the wires from the ignition coil.
3. Remove the Ignition Coil: Remove the screws or bolts that hold the ignition coil in place.
4. Install the New Ignition Coil: Install the new ignition coil and tighten the screws or bolts.
5. Connect the Wires: Connect the wires to the new ignition coil.
6. Set the Air Gap: Set the air gap between the ignition coil and the flywheel to the manufacturer’s specifications. This is typically done using a business card or a special air gap tool.
7. Test the Ignition System: Test the ignition system to ensure it is working properly.

Safety First: Protecting Yourself While Working

Working with chainsaws can be dangerous. Always wear appropriate safety gear, including:

Eye Protection: Safety glasses or a face shield to protect your eyes from flying debris.
Hearing Protection: Earplugs or earmuffs to protect your hearing from the loud noise of the chainsaw.
Gloves: Heavy-duty gloves to protect your hands from cuts and abrasions.
Chainsaw Chaps: Chainsaw chaps to protect your legs from accidental cuts.
Steel-Toed Boots: Steel-toed boots to protect your feet from falling logs and other hazards.
Helmet: A helmet is always a good idea when working with chainsaws.

Before starting any chainsaw repair, always disconnect the spark plug wire to prevent accidental starting.

Beyond the Fixes: Maintaining Your Husqvarna 440

Regular maintenance is essential for keeping your Husqvarna 440 running smoothly and preventing starting problems. Here are some tips:

Clean the Air Filter Regularly: A dirty air filter restricts airflow to the engine, leading to starting and running problems. Clean the air filter after each use, or more often if you’re working in dusty conditions.
Sharpen the Chain Regularly: A dull chain requires more effort to cut, putting strain on the engine and increasing the risk of kickback. Sharpen the chain regularly, or replace it when it becomes excessively worn.
Use Fresh Fuel: Old fuel can break down and gum up the carburetor. Always use fresh fuel and add a fuel stabilizer if the saw will be sitting for extended periods.
Store the Chainsaw Properly: When storing the chainsaw, drain the fuel tank and run the engine until it stalls to remove any remaining fuel from the carburetor. This will prevent the carburetor from becoming clogged with fuel deposits. Store the chainsaw in a dry, safe place.
Regularly Inspect the Chainsaw: Regularly inspect the chainsaw for any signs of damage or wear. Check the fuel lines, spark plug, carburetor, and other components. Replace any worn or damaged parts immediately.

Case Study: Reviving a Neglected Husqvarna 440

I was called out to a local farm to help troubleshoot a Husqvarna 440 that had been sitting unused for several years. The owner said it hadn’t started in ages. After a quick inspection, I found the following:

Old, Stale Fuel: The fuel tank was full of old, stale fuel that smelled like varnish.
Clogged Fuel Filter: The fuel filter was completely clogged with debris.
Fouled Spark Plug: The spark plug was black and oily.
Gummed-Up Carburetor: The carburetor was gummed up with fuel deposits.

Here’s how I revived the chainsaw:

Drained the Old Fuel: I drained the old fuel from the fuel tank.
Replaced the Fuel Filter: I replaced the clogged fuel filter with a new one.
Cleaned the Spark Plug: I cleaned the spark plug with a wire brush and adjusted the spark plug gap.
Cleaned the Carburetor: I disassembled the carburetor and cleaned each component with carburetor cleaner.
Reassembled the Carburetor: I reassembled the carburetor and adjusted the adjustment screws to the manufacturer’s recommended settings.
Added Fresh Fuel: I added fresh fuel to the fuel tank.
Started the Chainsaw: After a few pulls on the starter cord, the chainsaw roared to life.

The owner was amazed that I was able to revive the chainsaw so easily. He had been ready to give up on it and buy a new one. This case study highlights the importance of regular maintenance and proper storage for keeping your chainsaw running smoothly.

Strategic Insights: Wood Processing and Firewood Preparation

Beyond the technical fixes, understanding the broader context of wood processing and firewood preparation can significantly improve your efficiency and productivity.

Wood Type Selection: Different wood types have different burning characteristics. Hardwoods like oak, maple, and ash burn longer and produce more heat than softwoods like pine and fir. However, softwoods are easier to split and ignite.
Green Wood vs. Seasoned Wood: Green wood is freshly cut wood that has a high moisture content. Seasoned wood has been dried for several months, reducing its moisture content. Seasoned wood burns more efficiently and produces less smoke than green wood.
Felling Techniques: Proper felling techniques are essential for safety and efficiency. Always plan your felling operation carefully and consider the tree’s lean, wind direction, and surrounding obstacles.
Debarking Logs: Debarking logs can help them dry faster and prevent insect infestations.
Splitting Firewood: Splitting firewood can be done manually with an axe or mechanically with a log splitter. Hydraulic log splitters are much faster and easier to use than manual axes, especially for large volumes of firewood.
Firewood Stacking: Proper firewood stacking is essential for drying and storing firewood. Stack the firewood in a well-ventilated area and cover it with a tarp to protect it from rain and snow.

Next Steps: Putting Your Knowledge to Work

Now that you have a better understanding of how to troubleshoot and fix a Husqvarna 440 that won’t start, it’s time to put your knowledge to work.

Gather Your Tools and Supplies: Before you start, make sure you have all the necessary tools and supplies, including a screwdriver, spark plug wrench, carburetor cleaner, fuel filter, spark plug, and fuel lines.
Follow the Troubleshooting Steps: Start by following the troubleshooting steps outlined in this guide.
Don’t Be Afraid to Ask for Help: If you’re not comfortable working on your chainsaw yourself, don’t be afraid to ask for help from a qualified repair shop.
Practice Regular Maintenance: Practice regular maintenance to keep your chainsaw running smoothly and prevent starting problems.

By following these steps, you can keep your Husqvarna 440 running like a champ and enjoy many years of reliable service.

Husqvarna 440 Won’t Start (5 Pro Fixes Every Arborist Needs)