45 Husqvarna Chainsaw Troubleshooting (5 Pro Fixes)

Let’s bust a myth right off the bat: that any chainsaw problem automatically means a trip to the repair shop. I’ve spent countless hours in the woods, relying on my Husqvarna chainsaws to get the job done. Over the years, I’ve learned to diagnose and fix many common issues myself. Trust me, with a little know-how, you can often get your 45 Husqvarna chainsaw back up and running without breaking the bank. This guide will give you the “pro fixes” I’ve learned over the years.

45 Husqvarna Chainsaw Troubleshooting: 5 Pro Fixes

My old Husqvarna 45 has been a workhorse for years. From felling small trees to bucking firewood, it’s seen it all. But like any machine, it occasionally throws a fit. I’ve learned that a little preventative maintenance and knowing how to troubleshoot common problems can save a lot of time and money. Let’s dive into some of the most common problems I’ve encountered and how I fixed them.

1. Chainsaw Won’t Start: Fuel and Spark are Key

The most frustrating problem? A chainsaw that simply won’t start. Before you panic, let’s focus on the essentials: fuel and spark.

Fuel System Check

Old Fuel: This is the #1 culprit. Modern gasoline degrades quickly, especially when mixed with 2-cycle oil. I always drain the fuel tank and carburetor if the saw has been sitting for more than a month. Fresh fuel is essential. I use a fuel stabilizer to extend the life of my fuel.
Fuel Filter: A clogged fuel filter restricts fuel flow. I remove the filter from inside the fuel tank (usually accessible with a small hook or bent wire) and inspect it. If it’s dirty or clogged, replace it. I keep a few spares on hand.
Fuel Lines: Check for cracks or leaks in the fuel lines. Over time, they can become brittle and fail. I carefully inspect the lines from the fuel tank to the carburetor. If they’re damaged, replace them.
Carburetor: The carburetor mixes fuel and air. A dirty or gummed-up carburetor can prevent the saw from starting. Carburetor cleaner can sometimes help, but a complete carburetor rebuild might be necessary for stubborn cases.
- Personal Experience: I once spent an entire afternoon trying to start my Husqvarna 45 after it had been sitting for a few months. I replaced the fuel, checked the spark, and still nothing. Finally, I disassembled the carburetor and found it completely clogged with old fuel residue. After a thorough cleaning and reassembly, the saw fired right up.

Spark System Check

Spark Plug: A faulty spark plug can prevent the saw from starting. I remove the spark plug and inspect it. It should be clean and dry. If it’s fouled or wet, clean or replace it.
Spark Test: I use a spark plug tester to check for spark. If you don’t have a tester, you can carefully ground the spark plug against the engine block while pulling the starter cord. You should see a strong, blue spark. If there’s no spark, the ignition coil might be faulty.
Ignition Coil: The ignition coil generates the high voltage needed to create a spark. If the spark plug is good and there’s still no spark, the ignition coil might be the problem. Testing an ignition coil requires a multimeter and some technical knowledge. If you’re not comfortable with this, it’s best to take the saw to a qualified repair shop.
Kill Switch: Occasionally, the kill switch can malfunction and prevent the saw from starting. I disconnect the kill switch wire to see if that resolves the issue. If it does, replace the kill switch.
- Measurement: A healthy spark plug gap for a Husqvarna 45 is typically between 0.020 and 0.025 inches. I use a feeler gauge to ensure the gap is correct.

Takeaway: When your chainsaw won’t start, systematically check the fuel and spark systems. Start with the simplest things, like fresh fuel and a clean spark plug, and then work your way through the more complex components.

2. Chainsaw Starts But Dies Immediately: Carburetor Adjustments and Air Leaks

So, your chainsaw starts, but it sputters and dies right away? This often points to a problem with the carburetor or an air leak.

Carburetor Adjustments

Idle Speed Adjustment: The idle speed adjustment screw controls how fast the engine idles. If the idle speed is set too low, the engine will stall. I turn the idle speed adjustment screw clockwise to increase the idle speed.
High and Low Speed Adjustments: The high and low speed adjustment screws control the fuel mixture at high and low speeds. Incorrect adjustments can cause the engine to stall or run poorly. I make small adjustments to these screws, paying close attention to how the engine responds.
Factory Settings: It’s always a good idea to start with the factory settings for the carburetor adjustments. These settings are usually listed in the owner’s manual. I use the factory settings as a baseline and then make small adjustments as needed.
- Caution: Carburetor adjustments can be tricky. If you’re not comfortable with this, it’s best to consult a qualified repair shop.

Air Leaks

Intake Manifold: The intake manifold connects the carburetor to the engine. Cracks or leaks in the intake manifold can cause the engine to run lean and stall. I inspect the intake manifold for cracks or leaks.
Crankshaft Seals: The crankshaft seals prevent air from leaking into the engine. Worn or damaged crankshaft seals can cause the engine to run poorly. Checking the crankshaft seals requires specialized tools and knowledge. If you suspect a crankshaft seal leak, it’s best to take the saw to a qualified repair shop.
Hose Connections: Check that all hoses are properly connected and secured with clamps. Loose connections can lead to air leaks.
- Original Insight: I once had a Husqvarna 45 that would start and then die immediately. I spent hours adjusting the carburetor, but nothing seemed to work. Finally, I noticed a small crack in the intake manifold. After replacing the manifold, the saw ran perfectly.

Takeaway: If your chainsaw starts but dies immediately, check the carburetor adjustments and look for air leaks. Small adjustments to the carburetor can often resolve the issue, but air leaks require more extensive repairs.

3. Chainsaw Runs Poorly: Air Filter and Exhaust Issues

A chainsaw that runs poorly, lacks power, or smokes excessively often has issues related to air intake or exhaust.

Air Filter

Clogged Air Filter: A clogged air filter restricts airflow to the engine, causing it to run poorly. I remove the air filter and inspect it. If it’s dirty, clean it with soap and water or compressed air. Replace the air filter if it’s damaged.
Air Filter Type: Ensure you’re using the correct type of air filter for your Husqvarna 45. Using the wrong filter can restrict airflow or allow dirt to enter the engine. I always check the owner’s manual to confirm the correct filter type.
- Frequency: I clean my chainsaw’s air filter after every 5-10 hours of use, or more frequently if I’m working in dusty conditions.

Exhaust System

Spark Arrestor Screen: The spark arrestor screen prevents sparks from escaping the exhaust. A clogged spark arrestor screen restricts exhaust flow, causing the engine to run poorly. I remove the spark arrestor screen and clean it with a wire brush.
Exhaust Port: The exhaust port can become clogged with carbon buildup, restricting exhaust flow. I carefully clean the exhaust port with a scraper or wire brush.
Muffler: A damaged or corroded muffler can restrict exhaust flow. Inspect the muffler for damage and replace it if necessary.
- Case Study: A local logger I know was complaining about his Husqvarna 45 losing power. He had tried everything, but nothing seemed to work. I suggested he check the spark arrestor screen. Sure enough, it was completely clogged with carbon. After cleaning the screen, the saw ran like new.

Takeaway: A chainsaw that runs poorly often has issues related to air intake or exhaust. Regularly clean the air filter and spark arrestor screen to maintain optimal performance.

4. Chainsaw Chain Problems: Tension, Sharpness, and Lubrication

A dull chain, improper tension, or lack of lubrication can significantly impact a chainsaw’s performance and safety.

Chain Tension

Proper Tension: The chain should be tight enough to stay on the bar but loose enough to be pulled around by hand. I adjust the chain tension by loosening the bar nuts and turning the tensioning screw.
Too Tight: A chain that’s too tight will bind and wear out quickly. It can also damage the bar and sprocket.
Too Loose: A chain that’s too loose can derail and cause injury. It can also damage the bar and sprocket.
- Tip: I check the chain tension frequently, especially when the chain is new. New chains tend to stretch quickly.

Chain Sharpness

Dull Chain: A dull chain requires more force to cut, increasing the risk of kickback. I sharpen the chain regularly using a chainsaw file or a chain grinder.
Sharpening Angle: It’s important to maintain the correct sharpening angle when sharpening the chain. I use a chainsaw file guide to ensure the correct angle.
Chain Grinder: A chain grinder makes sharpening the chain faster and easier. I use a chain grinder for heavily damaged chains.
- Metric: A properly sharpened chainsaw chain should produce long, thin shavings. If the chain is producing dust, it’s dull.

Chain Lubrication

Chain Oil: Chain oil lubricates the chain and bar, reducing friction and wear. I always use high-quality chain oil.
Oil Level: Check the oil level frequently and refill as needed. Running the chainsaw with low oil can damage the chain and bar.
Oil Pump: If the chain isn’t being properly lubricated, the oil pump might be faulty. I check the oil pump for clogs or damage.
- Personal Story: I once ruined a perfectly good chainsaw bar because I forgot to check the oil level. The chain overheated and seized, damaging the bar beyond repair. I learned my lesson the hard way.

Takeaway: Proper chain tension, sharpness, and lubrication are essential for chainsaw performance and safety. Regularly check and maintain these components to prevent problems.

5. Chainsaw Overheating: Cooling System and Fuel Mixture

An overheating chainsaw can lead to serious engine damage. Common causes include a clogged cooling system or an improper fuel mixture.

Cooling System

Cooling Fins: The cooling fins on the cylinder head dissipate heat. I clean the cooling fins regularly to remove dirt and debris.
Airflow: Ensure that the airflow around the engine is not obstructed. Remove any debris that might be blocking the airflow.
Fan: The fan on the flywheel circulates air around the engine. I inspect the fan for damage and replace it if necessary.
- Maintenance Schedule: I clean the cooling fins on my Husqvarna 45 every 25 hours of use, or more frequently if I’m working in dusty conditions.

Fuel Mixture

Rich Mixture: A rich fuel mixture (too much fuel, not enough air) can cause the engine to overheat. I adjust the carburetor to lean out the fuel mixture.
Lean Mixture: A lean fuel mixture (not enough fuel, too much air) can also cause the engine to overheat. I adjust the carburetor to richen the fuel mixture.
Fuel Type: Using the wrong type of fuel can cause the engine to overheat. I always use the fuel type recommended by Husqvarna.
- Data Point: A 2-cycle engine typically requires a fuel-to-oil ratio of 50:1. Using a higher oil ratio can cause the engine to run rich and overheat.

Other Causes

Dull Chain: A dull chain requires more force to cut, causing the engine to work harder and overheat.
Heavy Load: Cutting large logs or working for extended periods can cause the engine to overheat. I allow the engine to cool down periodically to prevent overheating.
- Expert Advice: A seasoned logger once told me, “Treat your chainsaw like you treat yourself. Don’t push it too hard, and give it a break when it needs it.”

Takeaway: Overheating can cause serious engine damage. Regularly clean the cooling system and ensure the fuel mixture is correct to prevent overheating.

Advanced Troubleshooting: When to Call a Pro

While I’ve covered many common issues you can address yourself, some problems require a professional. Don’t hesitate to seek expert help if:

You’re not comfortable working on the chainsaw. Safety is paramount.
You’ve tried the above fixes and the problem persists. It might be a more complex issue.
The engine has internal damage. Major repairs often require specialized tools and knowledge.

Preventative Maintenance: The Best Defense

The best way to avoid chainsaw problems is to perform regular preventative maintenance. Here’s my checklist:

Clean the air filter regularly.
Sharpen the chain frequently.
Check the chain tension.
Lubricate the chain and bar.
Clean the cooling fins.
Use fresh fuel and oil.
Inspect the chainsaw for damage.
Store the chainsaw properly.
- Time Saver: I keep a logbook of all maintenance performed on my chainsaws. This helps me track when maintenance is due and identify potential problems early on.

Chainsaw Safety: Always a Priority

Before I wrap up, a crucial reminder: chainsaw safety. Always wear appropriate safety gear, including:

Eye protection
Hearing protection
Gloves
Chaps
Steel-toed boots

Never operate a chainsaw if you’re tired, distracted, or under the influence of drugs or alcohol.

Conclusion: Keep Your 45 Husqvarna Running Strong

With a little knowledge and preventative maintenance, you can keep your 45 Husqvarna chainsaw running strong for years to come. Remember to focus on the fundamentals: fuel, spark, air, and chain maintenance. And don’t be afraid to seek professional help when needed. Now get out there and get cutting!

45 Husqvarna Chainsaw Troubleshooting (5 Pro Fixes)