Stihl 038 AVS Chainsaw Tips (5 Pro Fixes For Farm Boss)

It’s estimated that nearly 2.4 billion people worldwide rely on wood for cooking and heating, highlighting the ongoing importance of efficient wood processing and firewood preparation. For many, myself included, the Stihl 038 AVS chainsaw, fondly known as the “Farm Boss,” has been a reliable workhorse in these endeavors. This guide shares my insights, gained from years of hands-on experience, on keeping your Stihl 038 AVS running smoothly. I’ll cover five pro fixes to keep your Farm Boss roaring, ensuring you’re not left in the lurch when the temperature drops or the workload increases.

Stihl 038 AVS Chainsaw Tips: 5 Pro Fixes for Farm Boss

The Stihl 038 AVS is a legend. Its reputation for power and durability is well-earned. However, even the best tools require maintenance and occasional repairs. As someone who’s spent countless hours felling trees, bucking logs, and splitting firewood, I know firsthand the frustration of a chainsaw that isn’t performing at its best. These five fixes address some of the most common issues I’ve encountered with the 038 AVS, ensuring it remains a dependable partner in your wood processing endeavors.

1. Carburetor Calamities: Tuning for Top Performance

A properly tuned carburetor is the heart of your chainsaw’s performance. A poorly adjusted carb can lead to hard starting, poor idling, stalling, and a loss of power. I’ve seen firsthand how a simple adjustment can breathe new life into a sluggish saw.

Understanding the Carburetor:

The carburetor mixes air and fuel in the correct proportions for combustion. The Stihl 038 AVS typically has three adjustment screws:

L (Low): Adjusts the fuel mixture at idle speed.
H (High): Adjusts the fuel mixture at high speed.
LA (Idle Speed): Adjusts the engine’s idling speed.

The Tuning Process:

Warm-Up: Start the chainsaw and let it warm up for a few minutes. This ensures the engine is at its operating temperature.
Idle Adjustment (L & LA):
- Turn the “L” screw clockwise until the engine starts to slow down or stall.
- Then, slowly turn the “L” screw counterclockwise until the engine runs smoothly at idle.
- Use the “LA” screw to adjust the idle speed so the chain doesn’t move when the throttle is released. The ideal idle speed is typically around 2,500 – 2,800 RPM (revolutions per minute), but refer to your owner’s manual for specific recommendations.
High-Speed Adjustment (H):
- Carefully accelerate to full throttle.
- Listen to the engine. If it sounds “four-stroking” (a sputtering, uneven sound), it’s running rich (too much fuel). Turn the “H” screw clockwise slightly to lean out the mixture.
- If the engine sounds “screaming” or “lean,” it’s running lean (not enough fuel). Turn the “H” screw counterclockwise slightly to richen the mixture.
- The goal is to find the sweet spot where the engine runs smoothly at full throttle without four-stroking or screaming.
Fine-Tuning: After making adjustments, let the engine run for a few minutes and re-evaluate. Small adjustments can make a big difference.

Pro Tip: Always make small adjustments (1/8 of a turn or less) and test the engine after each adjustment. It’s easier to fine-tune incrementally than to over-adjust and have to start over.

Data Point: A study by the U.S. Forest Service found that properly tuned chainsaws can improve fuel efficiency by up to 15% and reduce emissions by 10%.

Case Study: I once encountered a logger who was ready to scrap his 038 AVS because it kept stalling. After a careful carburetor tuning session, the saw ran like new, saving him the cost of a replacement.

Troubleshooting:

Engine Stalls at Idle: Adjust the “LA” screw to increase the idle speed. If that doesn’t work, the “L” screw may need adjustment.
Engine Bogs Down at Full Throttle: The “H” screw may need adjustment. Also, check the air filter and fuel filter for clogs.
Hard Starting: Check the spark plug, fuel filter, and carburetor. A dirty carburetor is a common cause of hard starting.

Cost Considerations: A carburetor rebuild kit typically costs between $20 and $40. A new carburetor can range from $50 to $150. However, properly tuning the existing carburetor can often solve the problem without the need for replacement.

2. Ignition Issues: Spark Plug Secrets and Coil Checks

A faulty ignition system can prevent your chainsaw from starting or cause it to run erratically. The spark plug and ignition coil are the key components to inspect.

Understanding the Ignition System:

The ignition system generates the high-voltage spark that ignites the air-fuel mixture in the engine’s cylinder. The spark plug provides the gap for the spark, and the ignition coil provides the necessary voltage.

Spark Plug Inspection and Replacement:

Remove the Spark Plug: Use a spark plug wrench to remove the spark plug.
Inspect the Spark Plug:
- Look for signs of fouling (carbon buildup), oil contamination, or damage to the electrode.
- The color of the electrode can indicate engine problems:
  - Tan or Light Gray: Indicates a healthy engine.
  - Black and Sooty: Indicates a rich fuel mixture or a dirty air filter.
  - Oily: Indicates oil contamination.
  - White or Blistered: Indicates a lean fuel mixture or overheating.
Clean or Replace the Spark Plug:
- If the spark plug is fouled but otherwise in good condition, clean it with a wire brush or spark plug cleaner.
- If the spark plug is damaged or heavily fouled, replace it with a new one. Refer to your owner’s manual for the correct spark plug type. A common spark plug for the Stihl 038 AVS is a Bosch WSR6F or NGK BPMR6A.
Check the Spark Plug Gap: Use a spark plug gap tool to ensure the gap between the electrode and the ground electrode is correct. The recommended gap for the Stihl 038 AVS is typically 0.020 inches (0.5 mm).
Install the Spark Plug: Tighten the spark plug to the manufacturer’s recommended torque specification. Overtightening can damage the cylinder head.

Ignition Coil Testing:

If the spark plug is in good condition but the chainsaw still won’t start, the ignition coil may be faulty.

Visual Inspection: Check the ignition coil for cracks, breaks, or other signs of damage.
Resistance Test: Use a multimeter to measure the resistance of the primary and secondary windings of the ignition coil. Refer to your owner’s manual for the correct resistance values. A significant deviation from the specified values indicates a faulty coil.
Spark Test:
- Remove the spark plug and connect it to the spark plug wire.
- Hold the spark plug against the engine block (to ground it).
- Pull the starter cord.
- Observe the spark plug gap. A strong, consistent blue spark indicates a healthy ignition coil. A weak, intermittent, or nonexistent spark indicates a faulty coil.

Pro Tip: Always disconnect the spark plug wire from the spark plug before performing any maintenance on the chainsaw. This prevents accidental starting.

Data Point: Studies show that replacing a faulty ignition coil can restore up to 30% of lost engine power.

Real Example: I recall a time when my 038 AVS suddenly died in the middle of a felling operation. After checking the spark plug and finding it to be heavily fouled, I replaced it with a new one, and the chainsaw fired right up.

Troubleshooting:

No Spark: Check the spark plug, ignition coil, and wiring connections.
Weak Spark: Replace the spark plug or ignition coil.
Intermittent Spark: Check the wiring connections and the ignition coil.

Cost Considerations: A new spark plug typically costs between $5 and $10. An ignition coil can range from $20 to $50.

3. Fuel System Foibles: Filter Finesse and Line Logistics

A clean and properly functioning fuel system is crucial for reliable chainsaw operation. Clogged fuel filters, cracked fuel lines, and a dirty fuel tank can all cause problems.

Understanding the Fuel System:

The fuel system delivers fuel from the fuel tank to the carburetor. It consists of the fuel tank, fuel filter, fuel lines, and fuel pump (in some models).

Fuel Filter Replacement:

Locate the Fuel Filter: The fuel filter is typically located inside the fuel tank, attached to the end of the fuel line.
Remove the Fuel Filter: Use a hooked wire or pliers to pull the fuel filter out of the fuel tank.
Inspect the Fuel Filter: Check the fuel filter for dirt, debris, or clogs.
Replace the Fuel Filter: Install a new fuel filter, ensuring it is securely attached to the fuel line.

Fuel Line Inspection and Replacement:

Inspect the Fuel Lines: Check the fuel lines for cracks, leaks, or hardening.
Replace the Fuel Lines: If the fuel lines are damaged, replace them with new fuel lines of the correct size and type. Use fuel-resistant tubing specifically designed for chainsaws.
Secure the Fuel Lines: Ensure the fuel lines are properly connected to the fuel tank, carburetor, and fuel filter. Use clamps to secure the connections.

Fuel Tank Cleaning:

Drain the Fuel Tank: Drain the fuel tank completely.
Rinse the Fuel Tank: Rinse the fuel tank with fresh fuel to remove any dirt or debris.
Dry the Fuel Tank: Allow the fuel tank to dry completely before refilling it with fuel.

Pro Tip: Always use fresh, high-quality fuel mixed with the correct ratio of two-stroke oil. Stale fuel can cause problems with the fuel system and engine. I always recommend using a fuel stabilizer, especially if the chainsaw will be stored for an extended period.

Data Point: Studies show that using fresh fuel and maintaining the fuel system can extend the life of a chainsaw engine by up to 25%.

Story Time: I once spent an entire afternoon troubleshooting a chainsaw that wouldn’t start, only to discover that the fuel filter was completely clogged with debris. A simple fuel filter replacement solved the problem.

Troubleshooting:

Chainsaw Won’t Start: Check the fuel filter, fuel lines, and fuel tank.
Chainsaw Runs Poorly: Check the fuel filter and fuel lines.
Fuel Leaks: Inspect the fuel lines and fuel tank for leaks.

Cost Considerations: A fuel filter typically costs between $3 and $5. Fuel lines can range from $5 to $10 per foot.

4. Oiling Obstacles: Pump Proficiency and Bar Bliss

Proper lubrication is essential for the longevity of the bar and chain. A malfunctioning oil pump or a clogged oiler system can lead to premature wear and damage.

Understanding the Oiling System:

The oiling system lubricates the bar and chain to reduce friction and wear. It consists of the oil tank, oil pump, oil lines, and oil outlet.

Oil Pump Inspection and Adjustment:

Locate the Oil Pump: The oil pump is typically located near the engine, driven by the crankshaft or clutch.
Inspect the Oil Pump: Check the oil pump for damage or wear.
Adjust the Oil Pump: Some oil pumps have an adjustable flow rate. Adjust the oil pump to provide adequate lubrication to the bar and chain. Refer to your owner’s manual for the adjustment procedure.

Oil Line Inspection and Cleaning:

Inspect the Oil Lines: Check the oil lines for cracks, leaks, or clogs.
Clean the Oil Lines: If the oil lines are clogged, clean them with compressed air or a small wire.
Replace the Oil Lines: If the oil lines are damaged, replace them with new oil lines of the correct size and type.

Bar and Chain Maintenance:

Clean the Bar and Chain: Regularly clean the bar and chain to remove dirt, debris, and pitch.
Sharpen the Chain: Keep the chain sharp to ensure efficient cutting. A dull chain puts extra strain on the engine and bar.
Lubricate the Bar and Chain: Use a high-quality bar and chain oil to lubricate the bar and chain.
Check the Bar Groove: Clean the bar groove to ensure proper oil flow.
Flip the Bar: Periodically flip the bar to distribute wear evenly.

Pro Tip: Use a bar and chain oil specifically designed for chainsaws. Motor oil or other types of oil may not provide adequate lubrication. I prefer using a bio-degradable bar and chain oil to minimize environmental impact.

Data Point: Studies show that proper lubrication can extend the life of a bar and chain by up to 50%.

Personal Story: I once neglected to check the oil level in my chainsaw and ended up running it dry. The bar quickly overheated and became damaged, requiring replacement. I learned my lesson the hard way.

Troubleshooting:

No Oil Flow: Check the oil tank, oil pump, oil lines, and bar groove.
Inadequate Oil Flow: Adjust the oil pump or clean the oil lines.
Bar Overheating: Ensure the bar and chain are properly lubricated.

Cost Considerations: A new oil pump can range from $30 to $70. Bar and chain oil typically costs between $10 and $20 per gallon.

5. Recoil Rewind Realities: Starter System Solutions

A malfunctioning recoil starter can be a major inconvenience, especially when you’re in the middle of a job. A broken starter rope, a damaged recoil spring, or a worn-out pawl can all cause problems.

Understanding the Recoil Starter:

The recoil starter is used to start the engine by manually turning the crankshaft. It consists of the starter rope, recoil spring, pawls, and starter pulley.

Starter Rope Replacement:

Remove the Starter Assembly: Remove the starter assembly from the chainsaw.
Remove the Old Starter Rope: Carefully remove the old starter rope from the starter pulley.
Install the New Starter Rope: Thread the new starter rope through the hole in the starter pulley and tie a knot at the end.
Wind the Recoil Spring: Wind the recoil spring by turning the starter pulley in the correct direction.
Reinstall the Starter Assembly: Reinstall the starter assembly on the chainsaw.

Recoil Spring Replacement:

Remove the Starter Assembly: Remove the starter assembly from the chainsaw.
Carefully Disassemble the Starter Assembly: Be very careful when disassembling the starter assembly, as the recoil spring is under tension and can cause injury if released suddenly.
Remove the Old Recoil Spring: Remove the old recoil spring from the starter assembly.
Install the New Recoil Spring: Install the new recoil spring in the starter assembly.
Reassemble the Starter Assembly: Carefully reassemble the starter assembly.
Reinstall the Starter Assembly: Reinstall the starter assembly on the chainsaw.

Pawl Inspection and Replacement:

Remove the Starter Assembly: Remove the starter assembly from the chainsaw.
Inspect the Pawls: Check the pawls for wear or damage.
Replace the Pawls: If the pawls are worn or damaged, replace them with new pawls.
Reinstall the Starter Assembly: Reinstall the starter assembly on the chainsaw.

Pro Tip: When replacing the starter rope or recoil spring, wear safety glasses and gloves to protect yourself from injury. I always recommend taking photos as you disassemble the starter assembly to help with reassembly.

Data Point: A properly functioning recoil starter can reduce the effort required to start a chainsaw by up to 40%.

Another Story: I once spent hours trying to start a chainsaw with a broken recoil spring. I eventually had to borrow a chainsaw from a neighbor to finish the job. I learned the importance of maintaining the recoil starter.

Troubleshooting:

Starter Rope Won’t Retract: Check the recoil spring.
Starter Rope Breaks: Replace the starter rope.
Chainsaw Won’t Start: Check the pawls.

Cost Considerations: A new starter rope typically costs between $5 and $10. A recoil spring can range from $10 to $20. Pawls typically cost between $5 and $10 per set.

Beyond the Fixes: General Maintenance for a Long-Lasting Farm Boss

These five fixes cover some of the most common issues I’ve encountered with the Stihl 038 AVS. However, regular maintenance is essential for keeping your Farm Boss running smoothly for years to come.

Air Filter Cleaning: Clean the air filter regularly to ensure proper airflow to the engine. A dirty air filter can cause the engine to run poorly and reduce its lifespan.
Cylinder Fin Cleaning: Keep the cylinder fins clean to prevent overheating.
Muffler Inspection: Inspect the muffler for damage or clogs. A clogged muffler can reduce engine power.
Regular Sharpening: Keep the chain sharp to ensure efficient cutting and reduce strain on the engine. Use a chainsaw file and follow the manufacturer’s instructions for sharpening.
Proper Storage: Store the chainsaw in a dry, well-ventilated area when not in use. Drain the fuel tank and run the engine until it stalls to prevent fuel from gumming up the carburetor.

Firewood Fundamentals: From Forest to Fireplace

While keeping your Stihl 038 AVS in top shape is crucial, understanding firewood preparation is equally important for efficient and effective wood burning.

Green Wood vs. Seasoned Wood:

Green Wood: Freshly cut wood contains a high moisture content (often over 50%). It’s difficult to ignite, produces excessive smoke, and burns inefficiently.
Seasoned Wood: Wood that has been allowed to dry for several months or years has a lower moisture content (ideally below 20%). It’s easier to ignite, produces less smoke, and burns hotter and more efficiently.

Data Point: Burning seasoned wood can increase heating efficiency by up to 30% compared to burning green wood.

Wood Species and Firewood Quality:

Different wood species have different properties that affect their suitability for firewood:

Hardwoods (e.g., Oak, Maple, Ash): Dense, burn slowly, produce a lot of heat, and create long-lasting coals.
Softwoods (e.g., Pine, Fir, Spruce): Less dense, burn quickly, produce less heat, and create less lasting coals. They also tend to produce more smoke and sparks.

The Seasoning Process:

Split the Wood: Splitting the wood increases the surface area exposed to air, speeding up the drying process.
Stack the Wood: Stack the wood in a single row, off the ground, and with good air circulation.
Protect from Rain and Snow: Cover the top of the wood stack with a tarp or roof to protect it from rain and snow.
Allow Time to Dry: Allow the wood to dry for at least six months, or preferably a year or more. Use a moisture meter to check the moisture content before burning.

Real Example: I once tried to burn green oak firewood and was frustrated by how difficult it was to ignite and how little heat it produced. After allowing it to season for a year, it burned like a dream.

Conclusion: Keeping the Farm Boss Roaring

The Stihl 038 AVS “Farm Boss” is a powerful and reliable chainsaw that can handle a wide range of wood processing tasks. By following these five pro fixes and practicing regular maintenance, you can keep your Farm Boss running smoothly for years to come. Remember, a well-maintained chainsaw is a safe and efficient tool. And with a good understanding of firewood preparation, you can ensure that you’re getting the most out of your wood-burning stove or fireplace.

Next Steps:

Review your owner’s manual for specific maintenance recommendations for your Stihl 038 AVS.
Gather the necessary tools and supplies for performing the fixes outlined in this guide.
Schedule regular maintenance sessions to keep your chainsaw in top condition.
Practice safe chainsaw operation techniques.

Additional Resources:

Stihl Dealers: Your local Stihl dealer can provide parts, service, and advice on maintaining your chainsaw.
Online Forums: Online forums dedicated to chainsaws and wood processing can be a valuable source of information and support.
YouTube Channels: Many YouTube channels offer tutorials on chainsaw maintenance and repair.

By investing in the proper maintenance and care of your Stihl 038 AVS, you’ll be rewarded with years of reliable service and the satisfaction of knowing you’re prepared for any wood processing challenge that comes your way. Now, go get that wood!

Stihl 038 AVS Chainsaw Tips (5 Pro Fixes for Farm Boss)