Why Is Fuel Stabilizer for Boats Needed for Boat Storage?

When it comes to boat storage during the off-season and winterization, plenty of things are on your to-do list before putting the boat away. You’ll certainly have your hands full from performing routine maintenance like an oil change or removing salt deposits from your lower unit. However, one of the most critical tasks is using a quality fuel stabilizer for boats.

Proper fuel treatment is essential to any long-term boat storage preparation plan. Failure to do so can cause severe damage to your engine and fuel system. Fuel system damage, in turn, often requires extensive troubleshooting and expensive repairs— all of which can be prevented with the simple and inexpensive addition of fuel stabilizers for boats throughout your fuel system.

To help you avoid catastrophe and ensure that your boat is stored correctly, we’ll take a look at everything you need to know about why fuel stabilizers for boats are a must, including:

• What is Fuel Stabilizer?
• Why Is Fuel Stabilizer for Boats Necessary?
• When to Use Fuel Stabilizer
• How to Use Marine Fuel Stabilizers and Treat Boat Fuel for Long-Term Storage
• How to Find a Quality Marine Fuel Stabilizer
• Finally, How to Choose a Quality Marine Fuel Stabilizer

Proper fuel treatment for boat storage means that starting your boat at the start of the next season can be as simple as turning the ignition key. Let’s begin!

What is Fuel Stabilizer?

As its name implies, a fuel stabilizer is a multi-function solution that stabilizes marine fuel sitting in a gas tank. The most common functions of fuel stabilizer are to:

• limit evaporation
• repel water infiltration
• prevent phase separation (a process where the ethanol content of marine fuel draws in water, creating a less-reactive fuel mixture).

Chemically, a fuel stabilizer is formulated from petroleum products, including a mixture of lubricants and antioxidants.

Why Is Fuel Stabilizer For Boats Necessary?

Two main reasons why a fuel stabilizer is an essential part of boat storage and as a supplement to regular boating are fuel preservation and corrosion. Let’s examine each of these aspects:

Fuel Preservation

Fuel is a dynamic liquid that changes in chemical composition from the moment it is refined until the time it enters your fuel system, ready for combustion. When fuel sits around, it can go bad from four factors in the environment that set accelerate reactions in the fuel. These factors are water, oxygen, light, and heat:

• Water and air provide oxygen to the fuel, enabling the chemical component of fuel destabilization to take place.
• Light and heat provide energy for these reactions to take place.

Boat storage is the perfect environment for all these factors, where temperatures can soar in the sun, and moist air can infiltrate microscopic leaks in your outboard’s fuel system.

How fast does fuel go bad? Unstabilized marine fuel starts to spoil after 30 days or less unless stored in an entirely airtight container. Unfortunately, the fuel system of most boats isn’t exactly airtight, introducing moisture that can significantly shorten this lifespan.

If you’ve left fuel sitting in your tank or your fuel lines for several weeks, the effects of destabilized gasoline change its quality.

• First, water will make the gas less reactive. This means a bad batch will become less combustible as the water:gas ratio increases. In extreme cases, less combustion means less mileage, engine bogs, and even completely unusable fuel.
• Second, fuel from the solution can form sticky resins that can quickly clog a carburetor or fuel injectors, also ruining performance.

So when it comes to long-term seasonal boat storage, you can expect an entire batch of fuel to become less combustible and hazardous to your boat if you haven’t treated it with a marine fuel stabilizer.

Corrosion Prevention

Corrosion of internal and external components of an outboard motor is the bane of any boater’s existence. Internal metal components, exposed to moisture, degrade over time due to metal oxidizing (rusting), causing leaks, pitting, and accelerated wear.

Most outboard motors are designed to withstand some internal damage and operate, but this corrosion-based damage is cumulative. A little rust leads to more rust. Before you know it, you’ll have to perform a massive overhaul on your outboard’s components (such as resurfacing your cylinder heads after replacing a head gasket)— time-consuming and expensive repairs.

Worse, leaks will likely occur due to pitting from corrosion, introducing even more moisture and air into the outboard. Eventually, this pitting leads to degraded performance on the water and eventual failure. In extreme cases, leaking gas fumes from corrosion can build in the engine compartment. That can lead to hazardous fumes and even explosions.

When to Use Fuel Stabilizer

The fuel quality will become noticeably worse the longer fuel sits. This is especially true for boat owners who tend to let their engines sit unused for more than three-four weeks. Obviously, during storage, your boat will sit for much longer.

The truth is that you should always use a marine fuel stabilizer every time you fuel up or intend to store your boat (see next section). Due to how inexpensive a fuel stabilizer is relative to its benefits, boaters should make it a habit and have a fuel stabilizer on hand to treat gas at each fill-up.

How to Use Fuel Stabilizers for Boats and Treat Boat Fuel for Long-Term Storage

Using a fuel stabilizer doesn’t just involve pouring a capful into the gas tank and calling it a day. Instead, stabilizing your fuel requires a bit of planning. You’ll want to use up most of the fuel in the boat’s tank and then fill it with fresh fuel just before it’s prepared for storage. The following steps will enable maximum protection and stabilization for boat storage:

1. Add a measured amount of fuel stabilizer to your tank.

Begin by making sure your boat has a nearly-empty tank of gas. Read the directions on the particular brand of fuel stabilizer you intend to use. Depending on the treat rate of the product (see “How to Choose a Quality Marine Fuel Stabilizer” section below), you may need to compare how much stabilizer is needed versus your entire fuel capacity.

Once you’ve done a basic calculation (ex. “Add one ounce of stabilizer per gallon”), measure the correct amount of stabilizer and pour it into the gas tank. Most stabilizers have a measuring cap or lines on the bottle that’ll help you measure the product.

2. Fill your tank with fuel.

Once the fuel stabilizer for boats has been added to your fuel tank, it’s time to fill up your tank almost completely with fuel. Use ethanol-free gasoline if possible. You’ll also want to leave a tiny space to accommodate the expansion of fuel during storage, so be sure not to overfill the tank.

Adding your marine fuel after the stabilizer ensures that the stabilizer is evenly dispersed in your fuel tank and minimizes the fuel tank’s exposure to moisture-rich air.

3. Run your engine(s) to distribute the fuel stabilizer.

Last, you’ll need to run your engine(s) to allow the fuel stabilizer to reach the entire fuel system. In most cases, 5 to 10 minutes of active run time is more than enough to do this properly. (Note: Always hook up your engines to a water source to prevent overheating

if you will be running your engine out of the water.)

By following these steps, when it comes time to pull your boat out of storage next season, you’ll be ready to hit the water as soon as possible!

How to Choose a Quality Marine Fuel Stabilizer

PartsVu sells several reliable fuel stabilizers thousands of boaters use for winterization, long-term storage, and every time you fill up your tank. Several reliable brands do the job well, but use your judgment in terms of which brand is best for you. To do so, consider the following criteria:

• Does the fuel stabilizer make realistic claims?
• Is the treat rate reasonable?

How long has the manufacturer been in business?

Longevity matters in the boat product world. The longer a fuel stabilizer manufacturer has been in business, the more likely they sell a quality product on which boaters can rely.

Does the fuel stabilizer make realistic claims?

Quality fuel stabilizers perform extremely well but pay attention to any excessive claims. Here are a couple of red flags:

• If the marine fuel stabilizer guarantees a substantial mileage gain (“35% mileage improvement – guaranteed!”), this is most likely a false claim.
• If the fuel stabilizer claims to kill microbes in fuel but does not have an EPA establishment number, this is a false claim.
• If the product claims to be able to reverse the effects of bad fuel, this is also a dubious claim. (see “Can a Fuel Stabilizer for Boats Reverse Bad Fuel?”).

Is the treat rate reasonable?

Treat rate is the recommended ratio of fuel stabilizer to fuel in your tank. The term “treat rate” is a bit counterintuitive, as the higher the treat rate, the more you’ll use it to reach the desired effect; conversely, a lower treat rate means you’ll use less.

Treat rate is often measured in ounces of stabilizer to gallons of fuel (i.e., “one ounce treats forty gallons of fuel”). It can be a bit misleading. Some multi-purpose fuel stabilizers have higher treat rates, while others make similar claims at lower treat rates. Generally speaking, a lower treat rate is most desirable.

Some of the most common treat rates for fuel stabilizers (single- and multi-purpose) include:

• 1:2000 (1 ounce treats approximately 18 – 20 gallons)
• 1:1000 (1 ounce treats approximately 8 – 10 gallons)
• 1:500 (1 ounce treats approximately 4 – 5 gallons)

For the treat rate, it’s reasonable for a multi-purpose fuel stabilizer to be at a treat rate of 1:2000 or higher. The higher the treat rate, the more volume the formulation has to put active ingredients together that perform what it claims on the bottle.

Q: What are the Best Fuel Stabilizers for Boats?

While there are a number of quality marine fuel stabilizers on the market, some of the brands we like include:

• Star brite’s Star Tron Enzyme Fuel Treatment (we actually wrote an article on this product – “Guide to Star Tron Enzyme Fuel Treatment & Other Star Tron Fuel Additives”)
• Yamalube Fuel Stabilizer and Conditioner Plus
• Mercury Quickstor
• Sta-Bil
• CRC

Q: Can a Fuel Stabilizer for Boats Reverse Bad Fuel?

No, fuel stabilizers are preventive treatments to stop the chemical reactions of instability from starting in your marine fuel. If fuel has turned stale, become darkened, or phase-separated, it’s best to empty the fuel system and replace it with fresh, stabilized fuel.

Q: Can Boat Fuel Stabilizer for Ethanol Also Prevent Water Problems?

Yes and no. Some fuel stabilizers and multi-function marine fuel additives are designed to treat small water problems depending on their formulation. However, if you have water in the fuel, it’s time to address the source of these water problems instead of costly recurring treatments.

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Now that you’ve learned the basics of fuel stabilizers, PartsVu is at your service for all your fuel stabilizer needs. Explore PartsVu today for everything you need to spend less time at the mechanic shop and more worry-free time out on the water!