Replacing Fuel Water Separator: Step-By-Step Guide For Diy Mechanics

Changing a fuel water separator is a crucial part of boat and vehicle maintenance. This task helps to ensure that your engine runs smoothly and efficiently by preventing water and impurities from entering the fuel system. While the process may vary slightly depending on the make and model of your boat or vehicle, the basic steps for changing a fuel water separator remain consistent. This guide will provide an overview of the tools required and the steps involved in changing a fuel water separator.

Characteristics of Changing a Fuel Water Separator

Cut off electricity and fuel lines

Before beginning any installation, it is imperative to cut off electricity and fuel lines to the boat. This is a crucial safety measure that will protect you from the risks of electrocution and fuel leakage. Here are some detailed instructions to guide you through this process:

Cut off Electricity:

• Locate the fuse box: Find the fuse box that houses the fuel pump fuse. It is usually located either in the interior of the boat or under the hood. Refer to your boat's manual for specific guidance.
• Remove the fuel pump fuse: Using needle-nose pliers or plastic tweezers, carefully remove the fuse for the fuel pump. This will prevent the fuel pump from functioning when you start the engine.
• Ensure the boat is not in gear: Make sure the boat is in park if it is an automatic, or in neutral with the parking brake engaged if it has a standard transmission.
• Start the engine: Insert the key and turn on the ignition to run the engine briefly. The engine will only run for a short time as it expends the remaining fuel in the system.
• Allow the engine to run briefly: Let the engine run for a minute or two before shutting it off. This will help relieve the pressure in the fuel lines.
• Re-insert the fuel pump fuse: Once the pressure is relieved and the engine is off, put the fuel pump fuse back in place. Return the cover to the fuse box and replace any trim pieces that were removed.

Cut off Fuel Lines:

• Open hatches for ventilation: Before manipulating any fuel lines, open all hatches to ensure proper ventilation in the boat.
• Identify the fuel hoses: Determine which fuel hoses will need to be disconnected or blanked during the installation process.
• Close the fuel valve: Locate the fuel valve at the tank and shut it off.
• Cut the supply hose: Using appropriate tools, carefully cut the supply hose at the mounting location. You may also choose to plug the line by inserting a bolt and securing it with a hose clamp.
• Drain the contents: After cutting the supply hose, carefully drain any remaining fuel into an appropriate container.

By following these steps, you will effectively cut off the electricity and fuel lines to your boat, creating a safer environment for performing maintenance and installation tasks. Remember to refer to your boat's manual for specific instructions and always prioritize safety when working with electrical systems and fuel lines.

Prepare the separator for installation

Before you begin, make sure you have all the necessary tools and supplies. For installing a fuel water separator, you will need:

• A drill with drill bits sized for the mounting holes
• A spanner (to install hose connectors and blanks)
• A boat fire extinguisher for safety
• A container to catch fuel
• Rags for post-installation cleanup
• A ball valve or blanking plugs to isolate the separator
• Fuel hoses for either end of the fuel water separator
• Jubilee clips/clamps for the fuel hoses

Now, unpack your separator and check that you have all the necessary fittings. Once you're sure that everything is there, you can begin assembling your fuel water separator. Refer to your unit's instructions for specific guidance on the assembly process, as this may vary depending on the model.

You may also want to pre-fill your separator with fuel. While this step is not necessary, pre-filling can help to displace air inside the separator and prevent large amounts of air from getting into your fuel system.

Locate a suitable spot

When locating a suitable spot for your fuel water separator, there are several factors to consider. Firstly, visibility and accessibility are important. You should place the separator in an area where you can easily check, drain, and replace the filter when necessary. This will also allow you to monitor the primer bulb, which should also be easily accessible.

Secondly, you need to ensure the location is clear of any moving hoses or cables that could rub against the separator. This will prevent any potential damage or interference with the separator's function.

The separator should be installed between the tank and the engine, or the primer bulb if it is an outboard engine. The hoses should be able to reach the engine and tank without kinking or making sharp turns.

Additionally, the separator should be oriented vertically, with the inlet and outlet fuel lines positioned conveniently. It should be placed in the fuel line going to the engine, but before any filters, primers, fuel pumps, or regulators.

Finally, if you are mounting the separator to the hull side, you will need to epoxy-glue a painted piece of plywood in place as a mounting plate.

Mark installation points and drill holes

Marking the installation points and drilling the mounting holes is a crucial step in installing a fuel water separator. Here is a detailed guide to help you through the process:

First, you need to identify the correct location for the fuel water separator. It should be placed in a visible and accessible location, allowing for easy inspection, drainage, and filter replacement. Ensure that the primer bulb is also easily accessible. The separator should be oriented vertically, and the inlet and outlet fuel lines should be positioned without any kinking. It should be placed in the fuel line going to the engine but before any filters, primers, fuel pumps, or regulators.

Once you have determined the suitable location, place the separator against the chosen spot. Use a pencil to mark the mounting holes. This step ensures that you drill holes in the exact locations required for mounting the separator securely.

Now it's time to drill the holes. Choose a drill bit that matches the size of the mounting holes. Carefully drill the holes at the marked points. Take your time with this step to ensure the holes are straight and neat.

After drilling the holes, it's important to prepare them for the fasteners. Inject a suitable sealant into the holes to ensure a tight and secure fit for the fasteners. This step helps to protect against any potential leaks and adds an extra layer of security.

Finally, fasten the fuel water separator to the mounting surface using the appropriate fasteners. Make sure to follow the manufacturer's instructions for the specific type of fasteners provided with your fuel water separator. Ensure that the separator is securely attached before proceeding to the next step of installing the valves and hoses.

Install the separator, valves and hoses

Now that you have prepared the fuel water separator for installation, it's time to install it along with the valves and hoses.

First, decide whether you will be using a ball valve for safety. If so, install it on the inlet side. This will allow you to block the fuel flow when replacing the filter. Apply a fuel sealant to the threaded section of the ball valve, then use a spanner to mount the ball valve to the separator.

Next, mount the hose connectors to the separator. Again, use a fuel sealant at the threads and a spanner to tighten the connectors. If there are any ports that need blanking, use blanking plugs or additional ball valves.

Now, take your hoses and place two clamps on each using jubilee clamps/clips. Ensure that your hose configuration follows the separator's arrow direction.

Connect the hoses to the hose connectors. Tighten all the jubilee clamps/clips.

Double-check that you have connected the hoses correctly: the hose from the tank should be attached to the "in" port, and the hose from the engine to the "out" port. Make sure the hoses are double-clamped firmly, but be careful not to pinch the rubber hoses.

If you need extra hose, use U.S. Coast Guard-approved Type A1-15 of the same diameter as the hose it's replacing.

Frequently asked questions