Replacing Stihl Fs 80 Fuel Line: Step-By-Step Guide

The Stihl FS80 is a trimmer that requires regular fuel line replacements, as the lines age quickly due to fuel impurities. This is a common issue across Stihl engines, and replacing the lines will help ensure that your engine runs smoothly.

To replace the fuel lines, first open the fuel tank cap and drain all old fuel into an approved container. You will then need to remove the fuel filter and air filter, as well as the choke cover plate and throttle cable. Next, remove the fuel return hose and fuel suction hose from the engine, and cut off two 6-inch lengths of fuel tubing, tapering one end of each line at a 45-degree angle. Using a metal wire, thread the new suction hose through the main fuel hole in the fuel tank, and coat the grommet with Stihl press fluid before pushing the hose down into place. Repeat this process for the return hose, and connect both hoses to their respective valves on the carburetor. Finally, push the new fuel filter into the suction hose, and refit the gas cap, air filter box, air filter, and filter cover.

Removing the old fuel lines

To remove the old fuel lines from your Stihl FS80 trimmer, you'll need to drain all the old fuel from the tank into an approved fuel container. You can then remove the fuel filter at the bottom of the tank by pulling it upward with a metal hook. Pull the fuel filter off the end of the suction hose.

Next, you'll need to remove the air filter cover and unhook the air filter. Remove the two mounting screws holding the air filter box in place. Take off the choke cover plate on top of the carburetor and unhook the throttle cable from the choke cover plate.

Now you can remove the fuel lines. Pull the fuel return hose off the stub next to the spacer flange. Then pull the fuel suction hose out of its seat on the carburetor. Pull both lines out of the engine and throw them away.

Sourcing the correct replacement parts

When it comes to replacing the fuel line on your Stihl FS 80, it's important to source the correct replacement parts to ensure a proper fit and maintain the performance of your equipment. Here are some detailed instructions on sourcing the right parts:

Identify the Correct Fuel Line Dimensions:

The Stihl FS 80 fuel line has specific dimensions that you need to match for a proper fit. The inner diameter (ID) of the fuel line should be 3.1mm, while the outer diameter (OD) is 5.7mm. This information can be crucial when searching for compatible fuel lines.

OEM (Original Equipment Manufacturer) Parts:

Stihl offers OEM fuel lines specifically designed for the FS 80 model. The part number for the fuel line is 0000 937 5004, and it is approximately 3 feet in length. You can purchase this fuel line directly from Stihl dealers or authorised retailers.

Aftermarket Parts:

There are also aftermarket options available that are designed to fit the Stihl FS 80. These are manufactured by third-party companies and can be purchased from online retailers or hardware stores. When considering aftermarket parts, pay attention to the dimensions and ensure they match the required specifications for your Stihl FS 80.

Fuel Line Kits:

To make the replacement process easier, consider purchasing a fuel line kit that includes additional components such as grommets and fuel filters. These kits often provide all the necessary parts for a complete fuel line replacement. For example, the Podoy FS80 Fuel Line Kit is a popular choice and includes two 1.5-foot fuel lines and five grommets.

Compatibility with Other Models:

It's worth noting that the Stihl FS 80 shares the same fuel line dimensions as other Stihl models, such as the FS80R, FS85, KM85, FC75, and BG75. Therefore, fuel lines and kits compatible with these models can also be used for your FS 80.

Additional Considerations:

When sourcing replacement parts, it's essential to consider the quality and durability of the fuel line. While some options may be more affordable, they might not offer the same level of performance and longevity as higher-quality parts. Additionally, always follow the manufacturer's recommendations and safety guidelines when performing any maintenance or repairs on your equipment.

Preparing the new fuel lines

To prepare the new fuel lines for your Stihl FS 80, you will need to cut the lines to the correct length and then shape one end of each line to ensure a secure connection.

Firstly, cut two lengths of fuel tubing, each about 6 inches long. You can use a fuel line kit or buy the tubing separately. The Stihl FS 80 fuel line is 3.1mm x 5.7mm, but other sizes can work. For example, the Echo fuel line 90014 (3mm x 5mm) or 1/8" x 3/16" Tygon fuel line have been recommended by users.

Once you have the tubing, slice a 45-degree taper into one end of both lines. This taper will help guide the lines into their connections and ensure a secure fit.

Now your new fuel lines are ready to be installed. You can follow online guides for the specific steps to install the lines on your Stihl FS 80, but here is a general overview of the process:

• Remove the fuel tank cap and drain the old fuel into an approved container.
• Disconnect the fuel lines from the carburetor and carefully pull them out through the fuel tank.
• Feed the new lines into the fuel tank, using a metal wire to guide them through.
• Connect the lines to the carburetor, ensuring they are secure.
• Reattach the fuel tank cap and any other components you removed during the process.

Your Stihl FS 80 should now be ready to use with its new fuel lines!

Inserting the new fuel lines

To insert the new fuel lines, start by cutting off two lengths of fuel tubing, each about 6 inches long. Slice a 45-degree taper into one end of both lines. Next, take the metal wire and insert it into the suction hose. Push the wire and hose through the main fuel hole in the fuel tank. Once through, withdraw the wire.

Now, coat the grommet on the new suction hose with Stihl press fluid. Push the fuel suction hose down until the rubber lip is properly seated and the flange on the hose lies flat against the fuel tank. Next, coat the stub and end of the return hose with Stihl press fluid. Push the return hose until it stops against the stub.

Coat the other end of the return hose and the suction hose with Stihl press fluid. Connect the suction hose to the intake valve on the carburettor. Connect the return hose to the outtake valve on the carburettor. Make sure both hoses are properly secured against their respective valves.

Securing the new fuel lines

To secure the new fuel lines on your Stihl FS 80, begin by coating the grommet on the new suction hose with Stihl press fluid. Push the fuel suction hose down until the rubber lip is properly seated and the flange on the hose lies flat against the fuel tank.

Next, coat the stub and end of the return hose with Stihl press fluid. Push the return hose until it stops against the stub. Now, coat the other end of the return hose and the suction hose with Stihl press fluid.

Connect the suction hose to the intake valve on the carburetor and the return hose to the outtake valve. Ensure both hoses are properly secured against their respective valves.

Finally, pull the main fuel line up into the tank opening using a metal hook. Push the new fuel filter's nozzle firmly into the suction hose.

Your Stihl FS 80 is now ready to be reused.

Frequently asked questions