Do I Need a Fuel Water Separator on My Boat?

The average boat uses about one-tenth of a gallon of fuel per horsepower (hp) rating of your engine. On the surface, this doesn’t sound like a lot of fuel, but if you consider a 200 hp outboard will use approximately 20 gallons of fuel per hour, it doesn’t take long to realize the volume of fuel your engine will process per year. If you do not take the necessary safeguards to protect your boat’s engine, you could pass thousands of gallons of contaminated fuel and water through your engine system during a normal boating season. There are several types of fuel filters you can use to improve this situation, but a fuel water separator is one of the best, and most economical options.

Boaters may assume that all types of fuel perform the same way in their boat’s engine, but it’s not true. Whether you use regular or premium gasoline, diesel, or an ethanol blend, you have to ensure that it’s free of water and contaminants. A fuel water separator is a perfect solution for addressing this situation. It not only filters the contaminants from the fuel, it also separates the water from the fuel and prevents it from entering and causing damage to the sensitive components in your engine.

There are several different types of fuel water separators, and they work on a wide range of marine applications. If you want to protect your boat and keep its engine running as long as possible, you’ll need to do some research to select the best filter for your particular application. This article will address some key research areas.

What Is a Fuel Water Separator?

Boats have a vast range of components and use several complex systems to keep you moving across the water. Understanding the intrinsic relationships of these systems is extremely important for the safe and normal operation of your boat. At a minimum, you should understand your fuel system and the importance of incorporating a fuel water separator into this fuel system.

A fuel water separator is a type of filter that removes contaminants, debris, and water from your fuel before it can reach the engine. As the fuel enters the filter, dirt particles and other contaminants are filtered and retained by the filter media. Because water is denser than gas, the water sinks to a collection bowl at the bottom of the filter and is retained there. Some bowls will have a drain plug that you can unscrew to drain the water from the collection bowl, while filters without a drain plug will require the filter housing to be removed and the water to be dumped out of the filter housing.

A fuel water separator commonly known as a spin-on fuel filter works well as a primary filter as long as you properly inspect and maintain it. Water should be drained from the collection bowl and the entire unit should be inspected for damage and leaks on a monthly basis. You should also change the filter every 6 months or every 300 hours of operation. Lastly, for very high-performance systems, a spin-on fuel filter can also be used as a secondary filter, which can be placed in line after your primary filter but before the fuel intake to the engine. Whether you’re looking for an outboard fuel water separator or a diesel fuel water separator, these devices are a crucial necessity for your engine.

Why Do I Need One?

As the popularity of outboard motors increases, the need to protect these high-performance systems is also increasing. High-performance engines are becoming very lightweight and smaller in size, and the precision parts of your engine can easily become damaged if contaminated fuel or water vapors come in contact with these systems.

As most boat owners know, the price of your boat’s replacement parts can add up quickly, especially components for your engine. Keeping your fuel clean and free of water is a very simple way to prevent unnecessary damage to your engine and will extend the life of many of its components. A $70 fuel water separator is an inexpensive expenditure as compared to a $4,000 engine repair. Even if your boat doesn’t currently have a fuel water separator, we highly encourage you to install one. This added level of protection will improve the performance of your engine and protect other critical fuel system components.

How Do I Choose One?

Once you understand the need for a fuel water separator, you must decide where to purchase one and which one to choose. There are several factors to keep in mind. These include the filtration rating level, type of collection bowl, and the fuel consumption rate of your engine. Most fuel water separators perform a similar function, but they need the best possible internal components to do so effectively. There are different types of filters, and you must choose the right one for your needs.

One of the specifications of a fuel water separator is the filter media rating. This is usually expressed in microns. As a rule of thumb, the larger the micron, the larger the size of the particles it will pass through the filter. You can choose either 2-, 10-, or 30-micron filters. Most general marine applications use a 10-micron fuel filter water separator. For extra protection, you may want to install a smaller 2-micron filter as a secondary level of filtration.

The collection bowl is a key component of a fuel water separator. As the name suggests, it collects all the water that is filtered out of the fuel. These bowls can be made of clear plastic, aluminum, or metal. Clear plastic bowls offer an easy method to visually inspect how much water is in the collection bowl and often have a built-in drain plug. However, plastic drain bowls are sensitive to high heat environments such as enclosed inboard engine compartments. They are not recommended for use in these type of engine systems. On the other hand, an aluminum and steel drain bowl is well suited for high temperature environments, but there is no way to determine how full the drain bowl is, so they should be drained on a regular basis. We suggest draining the collection bowl weekly.

The next important factor is the fuel consumption rate of your filter. Typically, the larger the engine, the larger your fuel water separator should be. As mentioned above, the required flow rate of your fuel water separator is about 10 percent of the rating of your engine. Again, as an example, a 200-hp engine would require a 20-gallons-per-minute (GPH) filter.

To determine the best fuel water separator for your boat, we recommend taking these items into consideration, looking at product reviews, and doing your own research. There are many brands available, but at the very least, you should avoid the low cost off-shore brands. They typically don’t perform well in marine applications.

Where Can I Find the Best Fuel Water Separator?

The best way to protect your boat is to purchase the right equipment. A fuel water separator keeps water and contaminants out of your fuel. This protects your engine and other critical components.

Choosing a fuel water separator isn’t easy because of the various options available today. Find one with an effective filter and collection bowl, make sure that it matches the size and fuel consumption levels of your engine, and choose the best brand.

Clear Flow Filtration Systems offers a range of boat parts and services to improve your experience on the water. View all of our fuel water separators to get the best parts today.

Looking for a new boat? Check out Marine Title. You can do boat history and title searches for everything from ski-boats to mega-yachts.