Family enjoys a day on a boat

You Need a Marine Fuel Stabilizer

Bad Gas Can Spoil Your Outing

Estimated reading time 4:30

Should you use marine fuel additives? The truth is, a good marine fuel stabilizer will keep your personal watercraft running at high efficiency and help ensure reliable starts throughout the year. If you own a boat or personal watercraft, you may have experienced problems due to pump gasoline. This is true for both diesel and gas engines.


A boat that doesn’t start or run properly will spoil a weekend outing. Furthermore, you don’t want to be stranded on water and you don’t want to spend your weekend or vacation repairing your boat or watercraft. For this reason, spending a few dollars on a boat fuel additive, such as a marine fuel stabilizer, will save you money and headaches down the road.

Boats docked in a harbor

Marine Diesel Engines

Microbial growth, also known as a biological layer, is an issue that pertains to diesel marine engines. The layer occurs between the fuel and the water that collects at the bottom of the fuel tank. If tank contents are disturbed – for example – during tank filling, the microbial biomass becomes suspended in the fuel. This leads to many problems, including plugged fuel filters, blocked fuel lines, fouled fuel injectors, and engine damage.


The best way to deal with this is to get the water out of the tank. However, you should also treat the microbial growth by adding a biocide to kill the growing layer.


Additionally, treat your fuel with a high-quality diesel additive. Diesel All-In-One™ is a complete fuel conditioner. To begin with, it cleans injectors and pumps, boosts cetane, and replaces lost lubrication. Another key point is that Diesel All in One disperses water. Subsequently, it protects the diesel fuel tank from rust and corrosion.

filling marine craft with gasoline

Marine Gasoline & Ethanol

Watercraft that runs on gasoline has a different issue. The primary concern is the ethanol that’s blended with pump gas. Some marinas and gas stations carry ethanol-free gasoline. However, most do not.


Ethanol causes problems in starting, performance, and can lead to long-term maintenance expenses. Why is this? Firstly, ethanol is hygroscopic. In other words, it pulls the moisture out of the surrounding air inside your fuel tank. When enough water collects in the tank, a process known as phase separation takes place. It doesn’t take much water to cause phase separation.


Phase separation is when the ethanol bonds with water and separates from the gasoline. The ethanol/water cocktail settles to the bottom of the tank. Moreover, phase separation takes the octane with it. The result is less effective gasoline. Secondly, the separated mixture can interfere with lubricants and potentially cause significant damage when it burns through the engine.


In 2017, Boating Magazine tested a gallon of E10 gasoline (10% ethanol). The results showed that the tested fuel turned into about three ounces of water/ethanol and 61 ounces of unusable 77-octane gasoline. To illustrate, a 100-gallon boat fuel tank would have contained nearly 1/2-gallon of the ethanol sludge based on the test results.


Another thing to consider is that pump gas breaks down and degrades in as little as 90 days. To put it another way, the chemical properties of the fuel change as it sits in your tank. As a result, deposits form in the gas. Also, ethanol is a solvent. This wreaks havoc on the internal parts in your fuel system–including degradation of plastic, rubber, and other fuel system components. This is where a good fuel stabilizer for boats come into play.

Benefits of Fuel Treatment for Boats

Owners of gasoline-powered boats and personal watercraft should use a fuel additive to protect their fuel systems against the harmful effects of ethanol. This provides fuel stability protection.


They formulate many of today’s fuel stabilizers to both prevent the formation of gums and varnish and mitigate the effects of phase separation. Some of these products include lubrication to protect parts and prevent corrosion. Furthermore, they retard phase separation and keep small amounts of water in suspension.


As a side note, Boating Magazine also outlines a simple way that you can test your fuel for water contamination in case you’re worried there might be an issue.

VP Marine Fuel Additive – The Best Fuel Stabilizer for Boats

Fortunately, VP Racing Fuels has applied nearly 50 years of fuel science to produce Ultra Marine™. It’s a fuel additive designed to protect boats and watercraft and keep their engines running like new.


Ultra Marine is more than just a gas stabilizer for boats and other watercraft. It features a MIL-SPEC all-metal anti-corrosive package, detergent package, and of course, a robust phase separator inhibitor to stop ethanol issues and keep fuel fresh.


If you’re an owner or operator of a marina, Ultra Marine is a terrific and easy way to increase your margins. Simply purchase it in bulk and mix in into your pump gas.


Use Ultra Marine for gas engines and Diesel All-In-One for diesel engines. It’s a small investment that will protect your expensive watercraft and ensure fun days on the water for years to come.

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