Two-Stroke Fuel Tank: Replacing The Fuel Line

If you're looking to replace the fuel line in your two-stroke fuel tank, there are a few steps you should follow to ensure a safe and effective process. Firstly, it's important to secure the gas line with a clamp to prevent leaks and to keep dirt or debris from entering the line. This is a crucial step to ensure that your engine doesn't face any issues down the line. Next, you'll want to remove the old fuel line and discard it, making sure that no fuel spills in the process. Cut your new fuel line to size, if necessary, and attach it to your gas tank's fuel valve and the gas inlet on your carburetor. You may need to remove filters or other objects to access the correct spots. Finally, seal the new fuel line with the proper clamps to prevent fuel leakage.

'Local primer' carburetor fuel line routing

Local Primer Carburetor Fuel Line Routing

Local primer carburetors are a type of carburetor found in two-stroke engines. They feature a primer bulb built on top of the carburetor assembly. Understanding the fuel line routing in these carburetors is essential when performing maintenance or repairs.

There are typically three fuel lines in a local primer carburetor system. The first line is connected to the fuel filter and the carburetor, delivering fuel from the tank to the carburetor when the engine is running. The second line connects the carburetor to the primer bulb, sucking unused fuel back from the carburetor into the primer bulb. The third line then returns the unused fuel from the primer bulb to the fuel tank, where it is filtered again and returned to the carburetor.

It is common to forget the orientation of fuel lines after removing them, as manufacturers often do not mark the incoming and outgoing fuel ports. To determine the correct fuel line routing, a simple test can be performed. First, install the lines on the carburetor by guessing their orientation. Then, place the ends of both lines in two-stroke fuel (not water) and prime the bulb. If fuel is pushed out of the unfiltered line, the orientation is correct. If bubbles emerge from the line with the fuel filter, the lines must be switched and tested again.

It is important to note that the primer bulb in a local primer carburetor pulls fuel through the filtered fuel line and into the carburetor, and then pushes it out of the carburetor through the unfiltered return line. This is different from remote primer carburetors, where the primer assembly is separate from the carburetor body, adding a third line to the system.

'Remote primer' carburetor fuel line routing

Remote primer carburetors have a slightly more complex fuel line routing than local primer carburetors because of an additional third line. The primer assembly pulls fuel through the carburetor, not the other way around.

The first step is to determine which side of the primer is the input and which is the output. Attach fuel lines to the primer assembly, submerge in fuel, and prime the bulb. The line that does not produce bubbles is the one that must be attached to the carburetor, as this is the incoming fuel line.

Now, attach the incoming line on the primer assembly to one of the ports on the carburetor and attach a third fuel line to the other carburetor fuel line port. Submerge the ends of both fuel lines in fuel and test the line configuration by depressing the primer bulb.

If the primer bulb becomes stuck or returns very slowly, then the line configuration is incorrect and the test must be conducted again. If this happens, switch the positions of the fuel lines on the carburetor and perform the test again.

When the routing is correct, bubbles will emerge from the primer assembly's return line when the line routing is correct. If the primer assembly return line is lifted out of the fuel while priming, you will see fuel squirting from the line.

Removing the fuel line

To remove the fuel line from a two-stroke fuel tank, the first step is to remove the gas tank itself. Once the tank is free, the next step is to remove the gas line, ensuring that spillage is kept to a minimum. Clamping the line will help to prevent fuel spillage, as well as keeping dirt and debris out of the line.

When removing the line, it is important to secure it with a clamp to prevent leaks and to stop any dirt or debris from entering the line. This is especially important if you plan on reusing the fuel in the tank. If there is still gas in the tank, it should be poured into a suitable container using a clean funnel.

Once the fuel is removed, the tank should be inspected for any cracks, breaks, or other issues that might warrant a replacement. If there are cracks in the tank, it is recommended to replace it rather than attempting to repair it with additives.

After the fuel is drained and the tank is inspected, the next step is to clean the tank. This can be done with either a high-pressure water hose or with chemicals. If using the high-pressure water method, it is important to ensure that there is no water remaining in the tank before reattaching it to the engine.

Sizing and attaching the new fuel line

Once you have the correct fuel line, you can begin the installation process. Start by turning off the fuel valve and removing the old fuel line. Cut the new fuel line to size, if necessary, and then attach it to the gas tank's fuel valve and the gas inlet on the carburetor. Be sure to use the proper clamps to secure the fuel line and prevent any fuel leakage.

Some fuel lines may not require hose clamps for installation. For example, the BBR Tuning Heavy-Duty Fuel Line is designed to fit snugly without the need for additional clamps. Always refer to the manufacturer's instructions for proper installation procedures.

It is important to ensure that the fuel line is securely attached and sealed properly to prevent fuel leaks. Once the new fuel line is installed, you can restart the engine and test it to ensure it is functioning correctly.

Preventing fuel line failure

To prevent fuel line failure in a two-stroke fuel tank, regular inspection and maintenance are key. Here are some detailed steps to help prevent fuel line issues:

Inspect and Clean the Fuel Tank:

• Remove the fuel tank and secure the fuel line with a clamp to prevent leaks and the entry of dirt or debris.
• Inspect the tank for any cracks, breaks, or other damage. If cracks are present, replace the tank.
• Clean the tank using either a high-pressure water hose or chemical cleaning solutions. Ensure all debris is removed, and the tank is thoroughly dried before reattaching it to the engine.

Replace the Fuel Lines:

• As fuel lines can become hard and brittle over time, consider replacing them during tank maintenance to prevent future issues.
• Purchase replacement fuel lines that fit your specific engine model.
• Cut the new lines to the correct size, if necessary, and attach them using proper clamps to ensure a tight seal and prevent fuel leakage.

Check for Air Bubbles:

• Air bubbles in the fuel line can indicate a problem with the carb/needle-valve. Ensure there are no air bubbles present after reassembling the fuel system.
• If air bubbles persist, there may be an issue with the jet orientation or a low-pressure zone at the jet's location. Check and adjust as needed.

Use the Correct Fuel and Oil Mixture:

• For a smooth engine run, ensure you are using the correct fuel and oil mixture, specific to your engine's requirements.
• In some cases, using gasoline instead of methanol may cause issues due to the lower ignitability of gasoline.
• If using gasoline, consider adding castor oil to the mixture for its heat removal and impact-absorbing qualities.

By following these steps and conducting regular maintenance, you can help prevent fuel line failure and keep your two-stroke engine running smoothly.

Frequently asked questions