Is Ethanol Fuel Good for Boat Engines?

When it comes to operating a boat, one of the most important things to keep track of is your fuel.  After all, your engine isn't going to get you far with an empty fuel tank. So while you're at the gas station, you've probably asked yourself this exact question: is ethanol fuel good for boat engines? Can you use it instead of traditional fuel?

The short answer is that you can, as long as it's an E10 rated ethanol fuel or smaller. However, depending on when your boat was made along with the type of engine can all affect the answer as well. As such, here are the facts you'll want to know when using ethanol fuel with your boat engine:

What is Ethanol Fuel?

Ethanol fuel is very high proof alcohol made from products like corn, sugar cane, or what that is added to fuel. The reason is because it is an "oxygenate," because it helps reduce hydrocarbon emissions when added to fuel to reduce air pollution. Ethanol fuel is rated by the percentage of ethanol mixed in with gasoline fuel. E10 is 10% ethanol, E85 is 85% ethanol, and so forth.

One of the most important details to understand about ethanol fuel, especially when it comes to boats, is how it interacts with air. The common myth is that ethanol sucks water out of the air. The truth is a bit more complicated. What ethanol does do is collect water more easily than gasoline. So, if water sprays the side of your boat, heavy ethanol can cause a condensation build up overtime.

Because of its environmental friendliness, even your traditional gasoline sold in the store likely has a small percentage of ethanol mixed in with the fuel. As such, you can refuel your boat with low grade ethanol fuels. Heavy ethanol fuel mixtures can lead to engine damage, however. To explain why, you'll need to learn about Phase Separation:

Why is Heavy Ethanol Based Fuel Bad for Engines?

Ethanol fuel is a mixture of gasoline and ethanol. When pumped at the station, this gas mixture of blended together. However, if left stagnate over the course of 100 days, this mixture separates. Even worse, pure ethanol collects water more easily form the air, leading to your gas tank filling up with ethanol, gasoline, and water.

Boats are built to run on the water, but their engines are carefully designed to avoid letting water into the fuel tank or engine. As such, if you're going to use ethanol mixed gas, there are two tips you'll want to follow to avoid damaging your boat:

1: Make sure you either empty your fuel tank completely or run your boat at least every 60 days.

2: Try to stick with E10 gasoline or low. Higher ethanol mixtures will cause water ot build up faster, especially in engines built before 1990. Old boat engines were not designed with ethanol in mind.


Service Your Boat at Bakes Marine:

Shopping for boat parts or want to learn more about fuel ethanol? Then contact Bakes Marine today! Open Monday through Saturday, we're proud to be one of the longest dealers and boat service providers in the Northwest.  Reach out by phone or by e-mail if you would like help today!