Replacing The Fuel Line On Your Stihl Fs90r

The Stihl FS90R is a powerful trimmer that has been used by many professionals for years. However, like any machine, it requires maintenance and occasional repairs to keep it running smoothly. One common issue that users may encounter is the need to replace the fuel line. While this may seem like a daunting task, it is possible to do it yourself with the right tools and knowledge.

There are several ways to approach this repair, and different users have shared their methods online. One method involves removing the carburetor and carefully prying up the tab of the connector until it pops out. Another user recommends checking for debris and adjusting the carburetor to get the trimmer running smoothly again.

Whatever method you choose, it is important to be careful and methodical when working with machinery and fuel lines. Always ensure you have the correct parts and tools before beginning any repair work.

Removing the carburettor

To remove the carburettor from your Stihl FS90R trimmer, you will need to remove the air filter cover and the air filter itself.

Inside the air filter housing, you will find two nuts that hold the housing and the carburettor together. Remove these nuts, and the carburettor will come off over the two posts that connect it to the engine.

Be careful not to mix up the fuel lines when you remove the carburettor, as there are two smaller lines that go to and from the fuel tank, and a third, larger hose that runs from under the engine. This is likely a vacuum hose that drives the diaphragms to make the pumping operation work.

Spraying the connector with WD-40 and carefully prying up on the tab until it pops out can make it easier to remove the carburettor.

Spraying the connector with WD-40

When replacing the fuel line on a Stihl FS90 trimmer, you will need to remove the carburetor. This will give you access to the fuel line connector on the fuel tank. Spraying the connector with WD-40 will help to loosen it, making it easier to carefully pry up the tab until it pops out. This is a much easier method than trying to access the fuel line connector without removing the carburetor.

WD-40 is a water-displacing spray that has a number of uses, including loosening connectors. It is a handy product to keep around for DIY and automotive maintenance. When spraying the connector, ensure you are in a well-ventilated area and wear protective gloves. You should also place a cloth or newspaper underneath the carburetor to catch any drips or excess spray.

Once you have sprayed the connector with WD-40, wait a few minutes for it to take effect. Then, using a small, flat-head screwdriver, carefully pry up the tab on the connector. It should pop out with a gentle force. If it does not, apply a little more WD-40 and try again. Be careful not to use too much force, as you could damage the connector or the surrounding components.

With the connector loose, you can now remove the fuel line. Gently pull it out, taking care not to bend or kink the line. If the line is difficult to remove, use a pair of needle-nose pliers to carefully grip the line and pull it out. Do not use excessive force, as this could damage the fuel line or the connector.

Now that the fuel line is removed, you can replace it with a new one. Insert the new fuel line into the connector and push it firmly into place. Ensure that it is securely connected before reinstalling the carburetor. With the new fuel line installed, your Stihl FS90 trimmer should be ready to use again and will last for many years if properly maintained.

Disconnecting the fuel line

Firstly, remove the carburettor. This will give you access to the fuel line connector. Once you have removed the carburettor, the next step is to spray this connector with WD-40, or a similar lubricant. This will help to loosen the connection and make it easier to disconnect the fuel line.

Now, carefully pry up the tab on the connector. You will need to apply a small amount of force, but be gentle to avoid any damage. The connector should pop out with a gentle force.

If you are having trouble removing the connector, you can try using a flat-head screwdriver to gently lever it out. Alternatively, you could try using a small knife, being extremely careful not to damage any surrounding components.

Once the connector is removed, you can then carefully lift the fuel line out of the fuel tank. It is important to be gentle during this step, as the fuel line is made of flexible rubber and can be easily damaged.

Finally, you will need to disconnect the fuel line from the carburettor. This connection is usually held in place with a small clamp or clip, which can be carefully removed using a pair of pliers or a screwdriver. Be sure to have a container ready to catch any remaining fuel in the line.

By following these steps, you should now have successfully disconnected the fuel line from your Stihl FS90R. Remember to always exercise caution when working with fuel lines, and ensure that you are working in a well-ventilated area.

Replacing the fuel filter

To replace the fuel filter on your Stihl FS90R, you'll first need to purchase a replacement fuel filter. These are available from Stihl dealers or online.

Once you have the new fuel filter, follow these steps:

• Remove the old fuel filter from the fuel line. It is likely held in place with a clamp or hose clip. Use a pair of pliers to gently squeeze the clamp and slide it back from the fuel filter.
• Carefully pull the fuel filter off the fuel line. It may be helpful to use a pair of needle-nose pliers to grip the fuel filter and avoid getting fuel on your hands.
• Take the new fuel filter and push it onto the fuel line, ensuring it is firmly seated.
• Slide the clamp back over the fuel filter and release the pliers to secure it in place.
• Prime the fuel line by depressing the primer bulb several times until the new fuel filter is filled with fuel.
• Start the engine and check for any leaks around the fuel filter or fuel lines.

It is important to note that you should always refer to the official Stihl FS90R manual for detailed instructions on replacing the fuel filter and perform this task with the engine turned off and cooled down.

Additionally, some Stihl models may have different fuel filter designs, so ensure you are using the correct replacement part for your specific model.

Adjusting the carburettor

Step 1: Before you begin, it is important to have a basic understanding of the carburettor screws. Typically, there are three types of screws: high speed, low speed, and idle. These screws form a triangle, with the top left being high speed, the top right being low speed, and the bottom being idle.

Step 2: To adjust the carburettor, start by setting the high and low-speed screws to 3/4 open. To get a sense of 3/4 open, turn the screws fully from left to right a few times.

Step 3: Once you have set the high and low-speed screws, you can adjust the idle screw. Start the engine and adjust the idle screw until the engine runs at a speed just below the point where the shaft starts turning.

Step 4: If the engine sputters, hesitates, or bogs down when accelerating, you may need to make a slight correction to the high-speed screw. Keep in mind that adjusting the high-speed screw will likely require you to readjust the idle screw as well.

Step 5: If you are still having issues with the carburettor, you may need to rebuild or replace it. This process involves removing and disassembling the carburettor, cleaning or replacing internal components, and reassembling it. It is recommended to refer to a repair manual or seek the help of a qualified technician for this process.

Step 6: Additionally, it is important to note that carburettor issues can sometimes be caused by factors other than the carburettor itself. For example, issues with the fuel line, fuel filter, or spark arrestor can impact the performance of the engine and may need to be addressed separately.

By following these steps and making the necessary adjustments, you should be able to fine-tune your Stihl FS90R carburettor for optimal performance.

Frequently asked questions