5 Easy Steps to Rebuild a Husqvarna Trimmer Carburetor

Has your Husqvarna trimmer been acting up lately? Maybe it’s sputtering and stalling, or maybe it’s just not running as smoothly as it used to. If the issue seems to be with the carburetor, don’t reach for a replacement just yet. Rebuilding the carburetor on a Husqvarna trimmer is a relatively simple task that can be completed with a few basic tools. In this article, we’ll provide you with a step-by-step guide on how to rebuild your Husqvarna trimmer carburetor. With clear instructions and helpful tips, you’ll be back to trimming your lawn in no time.

Before you begin, it’s important to gather the necessary tools and materials. You’ll need a small Phillips head screwdriver, a flathead screwdriver, a pair of pliers, a carburetor rebuild kit, and a can of carburetor cleaner. Once you have everything you need, you can start by removing the carburetor from the trimmer. To do this, locate the two screws that hold the carburetor to the engine and remove them. Then, carefully pull the carburetor away from the engine. Be careful not to damage the fuel lines or any other components.

With the carburetor removed, you can begin the rebuilding process. Start by disassembling the carburetor. This will involve removing the float bowl, the jets, and the diaphragm. Be sure to keep all of the small parts organized so that you can reassemble the carburetor correctly. Once the carburetor is disassembled, you can clean all of the parts with carburetor cleaner. Pay special attention to the jets, as they can easily become clogged with debris. After the parts are clean, you can reassemble the carburetor. Start by installing the diaphragm, followed by the jets and the float bowl. Finally, reattach the carburetor to the engine and tighten the screws.

Understanding Husqvarna Trimmer Carburetor

The carburetor in a Husqvarna trimmer is a crucial component responsible for mixing air and fuel to create a combustible mixture for the engine. It plays a vital role in the overall performance, efficiency, and longevity of the trimmer. Here’s an in-depth look at its components and how they interact to deliver the right air-fuel ratio:

Carburetor Components and Their Functions

Component	Function
Throttle Valve	Controls the amount of air entering the carburetor, regulates engine speed
Main Jet	Delivers fuel to the carburetor throat when the throttle valve is open
Idle Jet	Provides fuel to the carburetor when the throttle valve is closed or nearly closed during idling
Float Bowl	Stores fuel and maintains a constant fuel level in the carburetor
Float	Regulates the fuel level in the float bowl, prevents fuel overflow
Needle Valve	Controls the fuel flow into the float bowl, adjusts to maintain the correct fuel level
Venturi Tube	Narrowed section in the carburetor throat that creates a vacuum, drawing fuel from the main jet
Pilot Jet	Provides fuel to the carburetor when the throttle valve is partially open, transitions between idle and main jet operation

Step-by-Step Disassembly

Disassembling a Husqvarna trimmer carburetor can be a straightforward process with the right tools and some patience. Here’s a step-by-step guide to help you out:

1. Safety First

Before starting, ensure your trimmer is disconnected from the power source. Wear safety glasses and gloves to protect yourself from potential flying debris or fuel spillage.

2. Removing the Carburetor

Locate the carburetor on your trimmer. It’s usually a small, metallic component connected to the engine by hoses and fuel lines. Using a screwdriver, carefully disconnect all the hoses and fuel lines attached to the carburetor. Gently remove the carburetor from the engine, being cautious not to damage any components.

Once removed, inspect the carburetor for any visible damage or wear. If you notice any cracks, dents, or other irregularities, you may need to replace the entire carburetor.

Component	Description
Fuel Inlet	Connects to the fuel tank
Fuel Return Line	Returns excess fuel to the tank
Choke Lever	Activates the choke for starting
Throttle Lever	Controls the fuel-air mixture and engine speed
Idle Speed Screw	Adjusts the engine’s idle speed

Thorough Cleaning with Solvents

Now that the carburetor has been disassembled, it’s time to thoroughly clean it. For this step, you will need a carburetor cleaner and a soft brush or compressed air. Follow these steps:

Step 1: Soak the Parts

Dip the carburetor parts into a carburetor cleaner and let them soak for at least 15 minutes. This will help to dissolve any gunk or varnish that may have built up.

Step 2: Scrub the Parts

Once the parts have soaked, use a soft brush to gently scrub away any remaining dirt or debris. Pay special attention to the jets and passages, as these are areas where clogs can easily form.

Step 3: Rinse Thoroughly

After scrubbing, thoroughly rinse all of the carburetor parts with clean water. You can use a spray bottle or a running faucet. Make sure to remove all of the carburetor cleaner residue.

Step 4 (Optional): Dry with Compressed Air

If you have access to compressed air, you can use it to dry the carburetor parts. This will help to prevent any water spots or corrosion from forming.

Carburetor Cleaning Tools
Carburetor cleaner
Soft brush
Compressed air (optional)

Inspecting and Replacing Worn Components

Inspecting your Husqvarna trimmer’s carburetor for worn components is an important step in keeping your trimmer running smoothly. Here are some key components to check and replace as needed:

Floater Needle

The floater needle controls the fuel flow into the carburetor. If the needle is worn or damaged, it can cause the carburetor to overflow or run lean. To inspect the floater needle, remove the carburetor bowl and check for any signs of wear or damage. If the needle is worn, replace it with a new one.

Float

The float is a small, hollow device that floats on the fuel level in the carburetor bowl. As the fuel level rises, the float also rises, which in turn closes the floater needle and stops the fuel flow. If the float is damaged or filled with fuel, it can cause the carburetor to overflow or run lean. To inspect the float, remove the carburetor bowl and check for any signs of damage or fuel contamination. If the float is damaged or contaminated, replace it with a new one.

Main Jet

The main jet is a small brass tube that controls the fuel flow at higher engine speeds. If the main jet is clogged or damaged, it can cause the engine to run lean or bog down at high speeds. To inspect the main jet, remove the carburetor and unscrew the main jet. Check for any signs of clogging or damage. If the main jet is clogged, try cleaning it with a carburetor cleaner. If the main jet is damaged, replace it with a new one.

Reassembling the Carburetor

The final step in rebuilding the Husqvarna trimmer carburetor is reassembling it. This process is relatively simple, but it is important to follow the steps carefully to ensure that the carburetor is reassembled correctly.

Here are the steps on how to reassemble the Husqvarna trimmer carburetor:

Place the carburetor body gasket on the carburetor body.
Place the carburetor bowl on the carburetor body and secure it with the screws.
Place the throttle shaft into the carburetor body and secure it with the clip.
Attach the fuel line to the carburetor and secure it with the clamp.

Place the recoil starter assembly on the carburetor and secure it with the screws.

Installing the Recoil Starter Assembly

Installing the recoil starter assembly is a bit more involved than the other steps. Here is a detailed guide on how to do it:

Locate the recoil starter assembly and insert the rope into the hole in the center of the drum.
Wind the rope around the drum, making sure that it is evenly distributed.
Attach the spring to the recoil starter assembly and hook it onto the tab on the drum.
Secure the recoil starter assembly to the carburetor with the screws.
Test the recoil starter assembly by pulling on the rope. It should retract smoothly and easily.

Tuning the High-Speed Needle

The high-speed needle controls the fuel mixture for the engine at high speeds. To tune it properly, follow these steps:

1. Start the engine and let it warm up

This will ensure that the engine is operating at its normal operating temperature.

2. Turn the high-speed needle clockwise until the engine starts to run poorly

You should hear the engine start to bog down or stall.

3. Slowly turn the high-speed needle counterclockwise until the engine runs smoothly

This is the optimal setting for the high-speed needle.

4. Check the engine’s response

Quickly accelerate the engine and then release the throttle. The engine should respond quickly and smoothly.

5. Repeat steps 2-4 until the engine responds optimally

This may take several attempts.

6. Fine-tune the high-speed needle

Once the engine is running well, you can fine-tune the high-speed needle by turning it slightly clockwise or counterclockwise. This will help to improve the engine’s performance at high speeds.

7. Refer to the table below for troubleshooting tips

The HSN needle controls the air/fuel mixture at full throttle. Turning the needle clockwise will lean out the mixture and cause the engine to run hot. Turning the needle counterclockwise will enrich the mixture and cause the engine to run cool.

Symptom	Cause	Solution
Engine runs hot	HSN needle is too lean	Turn the HSN needle counterclockwise
Engine runs cool	HSN needle is too rich	Turn the HSN needle clockwise
Engine bogs down at high speeds	HSN needle is too lean	Turn the HSN needle counterclockwise
Engine accelerates poorly	HSN needle is too rich	Turn the HSN needle clockwise

Safety Precautions during Rebuilding

To ensure a safe and successful carburetor rebuilding process, adhere to the following precautions:

1. Disconnect the Spark Plug:

Disconnect the spark plug to prevent any accidental ignition during disassembly.

2. Keep Workspace Clean:

Maintain a clean work area to minimize the risk of dirt or debris entering the carburetor during reassembly.

3. Wear Safety Glasses:

Wear safety glasses to protect your eyes from any small particles or chemicals that may be released during disassembly.

4. Use a Clean Can of Carburetor Cleaner:

Utilize a fresh can of carburetor cleaner to effectively dissolve any deposits or debris within the carburetor.

5. Dispose of Used Parts Properly:

Dispose of any replaced or damaged parts responsibly to prevent environmental hazards.

6. Inspect All Parts Thoroughly:

Carefully inspect each component of the carburetor for any signs of wear, damage, or corrosion before reassembly.

7. Use a Torque Wrench for Tightening:

Tighten all screws and bolts using the specified torque values to ensure proper functioning and prevent overtightening.

8. Reassemble Carefully and Completely:

Follow the reassembly instructions meticulously, ensuring that all parts are properly aligned and secured. Refer to the carburetor diagram for guidance and to avoid any missing or incorrectly placed components. Double-check all connections and tighten all screws to the recommended torque specifications. Any overlooked or loosely fitted parts could compromise the carburetor’s performance and lead to operational issues. Thorough and precise reassembly is crucial for ensuring the carburetor functions optimally on your Husqvarna trimmer.

9. Test the Carburetor:

After reassembly, test the carburetor by starting the trimmer and adjusting the idle speed and air-fuel mixture to optimize performance.

Troubleshooting Common Carburetor Issues

9. Adjusting the Low-Speed Mixture Screw

The low-speed mixture screw controls the air-fuel mixture at low engine speeds. It is typically located on the side of the carburetor and is identified by a small screw with a spring around it. To adjust the low-speed mixture screw:

Symptom	Adjustment
Engine runs rich (黑煙) at low speeds	Turn the screw clockwise (顺时针) to lean out the mixture
Engine runs lean (白煙) at low speeds	Turn the screw counterclockwise (逆时针) to richen the mixture

Start by turning the screw fully clockwise until it stops, then turn it counterclockwise 1-1/2 turns. Start the engine and let it warm up. Adjust the screw in small increments (1/8 turn at a time) until the engine runs smoothly at low speeds without stalling.

Note: The optimal low-speed mixture setting will vary depending on the engine and carburetor model. Refer to the manufacturer’s instructions for specific adjustment guidelines.

Post-Rebuild Performance Testing

Once the carburetor has been rebuilt, it’s important to test its performance to ensure that it’s functioning properly. Here’s how to go about it:

Start the trimmer

Start the trimmer and let it run at idle for a few minutes to allow the engine to warm up.
Check for leaks

Inspect the carburetor and fuel lines for any signs of leaks. If you see any leaks, tighten the loose connections or replace the damaged components.
Adjust the idle speed

Adjust the idle speed screw until the engine runs smoothly at a speed of around 2,800 to 3,000 RPM. You can use a tachometer to measure the RPM.
Test the acceleration

Press the throttle trigger and check if the engine responds quickly and smoothly. There should be no hesitation or bogging down.
Test under load

Trim some grass to see how the carburetor performs under load. The engine should maintain its speed and power without stalling or surging.
Check the fuel mixture

Observe the exhaust gases from the engine. If the exhaust is black, the fuel mixture is too rich. If the exhaust is white, the fuel mixture is too lean. Adjust the carburetor settings accordingly.
Make further adjustments

If you encounter any issues during the performance testing, make further adjustments to the carburetor settings until the engine runs smoothly and efficiently.
Reassemble the trimmer

Once you’re satisfied with the performance of the carburetor, reassemble the trimmer and get back to work!
Troubleshooting

If you encounter any problems during the performance testing, refer to the troubleshooting guide in your trimmer’s manual for assistance.

By following these steps, you can ensure that your Husqvarna trimmer carburetor is rebuilt properly and is performing at its best.

How to Rebuild Husqvarna Trimmer Carburetor

Rebuilding a carburetor on a Husqvarna trimmer can be a challenging but rewarding task. By following these steps, you can restore your trimmer’s performance and extend its life.

Step 1: Gather your materials.

You will need:

A new carburetor kit
A Phillips screwdriver
A flathead screwdriver
A spanner wrench
A pair of pliers
A carburetor cleaner
A small brush

Step 2: Remove the carburetor from the engine.

Locate the carburetor on the engine and disconnect the fuel line. Remove the two bolts that secure the carburetor to the engine and remove the carburetor.

Step 3: Disassemble the carburetor.

Remove the top cover of the carburetor and set it aside. Remove the float bowl and float. Remove the main jet and idle jet.

Step 4: Clean the carburetor parts.

Spray carburetor cleaner on all of the carburetor parts and allow it to sit for several minutes. Use a small brush to remove any dirt or debris from the parts. Rinse the parts with clean water and dry them thoroughly.

Step 5: Reassemble the carburetor.

Install the main jet and idle jet in the carburetor. Install the float in the float bowl and install the float bowl on the carburetor. Install the top cover on the carburetor.

Step 6: Install the carburetor on the engine.

Place the carburetor on the engine and secure it with the two bolts. Connect the fuel line to the carburetor.

Step 7: Start the engine and adjust the carburetor.

Start the engine and allow it to warm up for a few minutes. Adjust the carburetor idle speed screw until the engine idles smoothly. Adjust the main jet screw until the engine runs at full throttle without surging or bogging down.