Stihl 024 AV Carburetor Replacement (5 Pro Tips For Smooth Cutting)

The Stihl 024 AV is a workhorse. I’ve spent countless hours in the woods with mine, felling small trees, limbing branches, and bucking logs for firewood. But like any tool subjected to constant use, the carburetor on your Stihl 024 AV will eventually need replacing. Wear and tear, fuel degradation, and internal clogging are all common culprits. Replacing the carburetor isn’t as daunting as it sounds, and with the right approach, you can get your saw back to its peak performance. That’s why I’ve put together these 5 pro tips to ensure a smooth cutting experience after your carburetor replacement.

Stihl 024 AV Carburetor Replacement: 5 Pro Tips for Smooth Cutting

Replacing the carburetor on your Stihl 024 AV is a task that can seem intimidating at first. However, with the right knowledge and a methodical approach, it’s a job any homeowner or small-scale logger can tackle. I’ve personally replaced countless carburetors on Stihl chainsaws over the years, and I’ve learned a few tricks along the way. These “pro tips” are designed to help you not only replace the carburetor successfully but also ensure your chainsaw operates at its optimal performance afterward.

1. Understanding the Need for Carburetor Replacement

Before diving into the replacement process, it’s crucial to understand why a carburetor needs replacing in the first place. Carburetors are responsible for mixing air and fuel in the correct ratio to create a combustible mixture for the engine. Over time, several factors can lead to carburetor failure:

Fuel Degradation: Modern gasoline often contains ethanol, which can attract moisture and cause corrosion within the carburetor’s delicate passages. This can lead to clogs and inconsistent fuel delivery. I’ve seen this firsthand when using gasoline that’s been sitting in the tank for too long – the saw would sputter and stall constantly.
Wear and Tear: The internal components of a carburetor, such as the diaphragms and needles, are subject to wear and tear over time. Diaphragms can become stiff and brittle, affecting their ability to regulate fuel flow.
Dirt and Debris: Even with a fuel filter, small particles of dirt and debris can find their way into the carburetor, clogging jets and passages.
Physical Damage: Sometimes, physical damage to the carburetor body or components can necessitate replacement.

Identifying Carburetor Problems:

Common symptoms of a failing carburetor include:

Difficulty Starting: The engine may be hard to start, or it may not start at all.
Rough Idling: The engine may idle erratically or stall frequently.
Poor Performance: The engine may lack power, especially when under load.
Excessive Smoke: The engine may produce excessive smoke, indicating an improper air-fuel mixture.
Fuel Leaks: The carburetor may leak fuel, which is a fire hazard.

If you’re experiencing any of these symptoms, it’s a good idea to inspect your carburetor. A visual inspection may reveal obvious problems, such as fuel leaks or damaged components. You can also try cleaning the carburetor, but if the problem persists, replacement is often the best solution.

2. Gathering the Right Tools and Parts

Before you start wrenching, make sure you have all the necessary tools and parts on hand. This will save you time and frustration.

Essential Tools:

Screwdrivers: You’ll need both flathead and Phillips head screwdrivers in various sizes. A set of precision screwdrivers is also helpful for adjusting the carburetor.
Pliers: A pair of needle-nose pliers and regular pliers will come in handy for removing fuel lines and other small parts.
Socket Set: A socket set with various sizes will be needed to remove the air filter cover and other components.
Wrenches: You may need a few wrenches to remove the carburetor mounting bolts.
Carburetor Cleaner: Use a dedicated carburetor cleaner to clean any remaining parts.
Clean Rags: Keep plenty of clean rags on hand to wipe up spills and clean parts.
Small Brush: A small brush, like a toothbrush, can be used to clean the carburetor body and other components.
Compressed Air: Compressed air is useful for blowing out any debris from the carburetor and other parts.
Spark Plug Wrench: You’ll want to inspect the spark plug while you’re at it.
Fuel Line Clamp Pliers: While not essential, these make disconnecting fuel lines much easier and prevent fuel spills.
Camera or Phone: Take pictures as you disassemble the saw. This helps you remember where everything goes during reassembly. I learned this lesson the hard way after spending hours trying to figure out where a small spring went!

Essential Parts:

New Carburetor: Purchase a replacement carburetor specifically designed for the Stihl 024 AV. I always recommend using genuine Stihl parts or reputable aftermarket brands. Avoid the cheapest options, as they often have poor quality and can cause more problems than they solve.
New Fuel Filter: Replace the fuel filter at the same time as the carburetor. A clogged fuel filter can restrict fuel flow and damage the new carburetor.
New Air Filter: A clean air filter is essential for proper engine performance.
New Fuel Lines: If your fuel lines are cracked or brittle, replace them. Old fuel lines can leak and cause fuel delivery problems.
New Spark Plug: Replacing the spark plug is a good idea, especially if it’s been a while since the last replacement.
Gaskets: Ensure you have all the necessary gaskets for the carburetor and intake manifold.

Safety Gear:

Safety Glasses: Protect your eyes from debris and chemicals.
Gloves: Wear gloves to protect your hands from fuel, oil, and sharp edges.

3. Step-by-Step Carburetor Replacement

With your tools and parts gathered, you’re ready to begin the carburetor replacement process. Here’s a detailed step-by-step guide:

Step 1: Preparation

Disconnect the Spark Plug Wire: This is a crucial safety step to prevent accidental starting of the chainsaw.
Drain the Fuel Tank: Drain any remaining fuel from the fuel tank into a suitable container. This will prevent fuel spills during the replacement process. I usually do this outside, away from any potential ignition sources.
Clean the Work Area: Clean your work area to prevent dirt and debris from entering the engine.

Step 2: Removing the Air Filter Assembly

Remove the Air Filter Cover: Use a screwdriver or socket wrench to remove the screws or clips that hold the air filter cover in place.
Remove the Air Filter: Carefully remove the air filter. Inspect it for dirt and damage. If it’s dirty, replace it with a new one.

Step 3: Disconnecting the Fuel Lines and Throttle Linkage

Locate the Fuel Lines: Identify the fuel lines connected to the carburetor. There will typically be two fuel lines: one from the fuel tank and one to the engine.
Disconnect the Fuel Lines: Use pliers or fuel line clamp pliers to carefully disconnect the fuel lines from the carburetor. Be prepared for some fuel to spill.
Disconnect the Throttle Linkage: Locate the throttle linkage connected to the carburetor. This linkage connects the throttle trigger to the carburetor’s throttle plate. Carefully disconnect the throttle linkage from the carburetor.
Disconnect Impulse Line: Most carburetors have an impulse line. Disconnect it carefully. This line uses crankcase pressure to operate the fuel pump within the carburetor.

Step 4: Removing the Old Carburetor

Remove the Carburetor Mounting Bolts: Use a wrench or socket wrench to remove the bolts that hold the carburetor to the intake manifold.
Remove the Carburetor: Carefully remove the carburetor from the intake manifold. Be careful not to damage the intake manifold or any surrounding components.

Step 5: Installing the New Carburetor

Install New Gaskets: Install new gaskets between the carburetor and the intake manifold. This will ensure a proper seal and prevent air leaks.
Mount the New Carburetor: Carefully mount the new carburetor onto the intake manifold.
Tighten the Mounting Bolts: Tighten the carburetor mounting bolts to the manufacturer’s specified torque. Overtightening can damage the carburetor or intake manifold.
Reconnect the Fuel Lines: Reconnect the fuel lines to the carburetor. Make sure the fuel lines are securely attached and properly routed.
Reconnect the Throttle Linkage: Reconnect the throttle linkage to the carburetor. Ensure the linkage moves freely and that the throttle plate opens and closes properly.
Reconnect the Impulse Line: Reconnect the impulse line to the carburetor.

Step 6: Reassembling the Air Filter Assembly

Install the Air Filter: Install the air filter. Make sure it’s properly seated in the air filter housing.
Install the Air Filter Cover: Install the air filter cover and tighten the screws or clips.

Step 7: Final Checks

Inspect Fuel Lines: Double-check all fuel lines for proper connection and routing.
Check Throttle Linkage: Verify the throttle linkage moves smoothly and the throttle plate opens and closes correctly.
Reconnect Spark Plug Wire: Reconnect the spark plug wire to the spark plug.

4. Carburetor Adjustment: The Key to Smooth Cutting

Replacing the carburetor is only half the battle. Proper carburetor adjustment is crucial for ensuring smooth cutting and optimal engine performance. Most carburetors have three adjustment screws:

“L” (Low-Speed) Screw: This screw adjusts the fuel mixture at idle and low speeds.
“H” (High-Speed) Screw: This screw adjusts the fuel mixture at high speeds.
“LA” (Idle Speed) Screw: This screw adjusts the engine’s idle speed.

Initial Adjustment:

Before starting the engine, perform an initial adjustment of the carburetor screws. This will provide a starting point for fine-tuning.

Turn the “L” and “H” Screws: Turn both the “L” and “H” screws clockwise until they are lightly seated. Then, back them out 1 to 1.5 turns. This is a good starting point for most Stihl 024 AV carburetors.
Adjust the “LA” Screw: Adjust the “LA” screw so that the throttle plate is slightly open. This will allow the engine to idle.

Fine-Tuning the Carburetor:

Once the engine is warmed up, you can fine-tune the carburetor for optimal performance.

Adjust the Idle Speed: Start the engine and let it warm up for a few minutes. If the engine stalls, turn the “LA” screw clockwise to increase the idle speed. If the engine idles too fast, turn the “LA” screw counterclockwise to decrease the idle speed. The ideal idle speed is when the engine runs smoothly without stalling, but the chain does not move.
Adjust the Low-Speed Mixture: Adjust the “L” screw for the smoothest idle. Turn the “L” screw slowly clockwise or counterclockwise until the engine idles smoothly and responds quickly to throttle input. If the engine hesitates or bogs down when you accelerate, the “L” mixture is too lean. If the engine smokes excessively or runs rough at idle, the “L” mixture is too rich.
Adjust the High-Speed Mixture: Adjust the “H” screw for optimal high-speed performance. This is best done while the chainsaw is under load, such as cutting a piece of wood. Turn the “H” screw slowly clockwise or counterclockwise until the engine runs smoothly and has good power. If the engine bogs down or loses power when cutting, the “H” mixture is too lean. If the engine smokes excessively or runs rough at high speed, the “H” mixture is too rich. Important Note: Running the engine too lean at high speed can cause engine damage. Err on the side of a slightly rich mixture. I had a friend who ignored this advice and ended up seizing his piston. It’s a costly mistake.

Important Considerations:

Consult the Owner’s Manual: Always consult the Stihl 024 AV owner’s manual for specific carburetor adjustment instructions and specifications.
Use a Tachometer: For precise carburetor adjustment, use a tachometer to measure the engine’s RPM. This will help you ensure the engine is operating within the manufacturer’s recommended range.
Listen to the Engine: Pay attention to the engine’s sound and performance. This will provide valuable clues about the carburetor’s adjustment.
Make Small Adjustments: Make small adjustments to the carburetor screws and wait a few seconds for the engine to respond.
Adjust in Increments: Avoid making large adjustments to the carburetor screws, as this can make it difficult to find the optimal setting.

5. Preventative Maintenance: Keeping Your Carburetor Healthy

Once you’ve replaced and adjusted your carburetor, it’s important to implement preventative maintenance practices to keep it running smoothly for years to come.

Use Fresh Fuel: Always use fresh, high-quality gasoline with the correct octane rating. Avoid using gasoline that has been sitting in the tank for more than a month or two. I always add a fuel stabilizer when storing my chainsaw for extended periods.
Use Fuel Stabilizer: Add a fuel stabilizer to the gasoline to prevent fuel degradation and corrosion.
Clean the Air Filter Regularly: Clean the air filter regularly to prevent dirt and debris from entering the engine.
Replace the Fuel Filter Regularly: Replace the fuel filter regularly to ensure a clean fuel supply to the carburetor. I usually replace mine every year or after every 50 hours of use.
Drain the Fuel Tank Before Storage: Before storing your chainsaw for an extended period, drain the fuel tank and run the engine until it stalls. This will prevent fuel from gumming up the carburetor.
Inspect Fuel Lines Regularly: Inspect the fuel lines regularly for cracks or leaks. Replace any damaged fuel lines immediately.
Store Chainsaw Properly: Store your chainsaw in a clean, dry place. This will help prevent corrosion and damage.
Consider an Aftermarket Fuel Cap: Some aftermarket fuel caps are designed to vent better, preventing vapor lock issues, especially in hot weather.
Avoid Over-Oiling the Chain: While chain oil is essential, excessive oiling can lead to oil accumulating around the carburetor, attracting dirt and debris.

Troubleshooting Common Issues After Carburetor Replacement:

Even after following these steps, you might encounter some issues. Here’s how to troubleshoot them:

Engine Still Won’t Start: Check for spark, fuel delivery, and compression. Ensure the spark plug is clean and properly gapped. Verify fuel is reaching the carburetor.
Engine Starts but Stalls Immediately: This often indicates a very lean idle mixture. Adjust the “L” screw richer (counter-clockwise). Also, check for air leaks around the intake manifold.
Engine Runs Rough or Bogs Down: This could be due to either a lean or rich mixture. Experiment with small adjustments to both the “L” and “H” screws.
Chain Moves at Idle: Adjust the “LA” screw counter-clockwise to decrease the idle speed until the chain stops moving.

By following these 5 pro tips, you can successfully replace the carburetor on your Stihl 024 AV and ensure it runs smoothly for years to come. Remember to prioritize safety, use the right tools and parts, and take your time. With a little patience and attention to detail, you’ll be back to cutting wood in no time.

Case Study: Reviving a Neglected Stihl 024 AV

I once acquired a Stihl 024 AV from a neighbor who was moving. It had been sitting in his shed for years, untouched. The fuel tank was full of old, gummy gasoline, and the carburetor was completely clogged. After draining the old fuel and thoroughly cleaning the chainsaw, I decided to replace the carburetor rather than attempt to rebuild the old one.

Following the steps outlined above, I replaced the carburetor, fuel filter, air filter, and spark plug. I also replaced the fuel lines, as they were brittle and cracked. After the replacement, the chainsaw started on the second pull! However, it was running very rough and smoking excessively.

Using a tachometer, I carefully adjusted the carburetor screws until the engine idled smoothly and had good power. It took some time and patience, but eventually, I got the engine running perfectly. The chainsaw is now a reliable workhorse that I use for various tasks around my property. This experience reinforced the importance of proper carburetor adjustment and preventative maintenance.

Strategic Insights for Small-Scale Logging Businesses

For small-scale logging businesses, chainsaw maintenance is crucial for maximizing productivity and minimizing downtime. Investing in high-quality replacement parts and tools is essential. Develop a preventative maintenance schedule for all chainsaws, including regular carburetor cleaning and adjustment. Train employees on proper chainsaw operation and maintenance procedures. By prioritizing chainsaw maintenance, you can reduce repair costs, extend the lifespan of your equipment, and improve overall efficiency.

Replacing a carburetor may seem daunting at first, but with the right knowledge and a methodical approach, it’s a task that anyone can tackle. Remember to prioritize safety, use the right tools and parts, and take your time. With a little patience and attention to detail, you’ll be back to cutting wood in no time.

Next Steps:

Now that you understand the process of replacing a Stihl 024 AV carburetor, it’s time to put your knowledge into practice.

Gather your tools and parts.
Follow the step-by-step instructions.
Adjust the carburetor for optimal performance.
Implement preventative maintenance practices.

Good luck, and happy cutting! Remember to always wear appropriate safety gear and follow all safety precautions when operating a chainsaw.

Stihl 024 AV Carburetor Replacement (5 Pro Tips for Smooth Cutting)