Ethanol And Boat Engines: A Recipe For Disaster?

Ethanol is a highly refined plant-based alcohol that is added to fuel to reduce hydrocarbon emissions. However, it has been known to cause engine damage, especially in boats. In this article, we will explore the effects of ethanol on boat engines and provide tips for preventing ethanol-related issues.

Ethanol's water-attracting properties can cause engine stoppage

Ethanol is a hygroscopic substance, meaning it attracts water. This is a particular problem for boats, as water from condensation often forms in their fuel tanks. When ethanol is present in the fuel, it attracts and absorbs this condensation. This can cause a boat engine to stop working due to water contamination or fuel phase separation.

When ethanol-blended fuel comes into contact with water, it can absorb some or all of that water. This can be beneficial, but fuel can reach a saturation point, and water can phase separate to form a distinct layer in the bottom of the tank. The upper "gasoline" layer will be depleted of ethanol and have a reduced octane level. The lower "phase separation" layer will be a corrosive mix of water and ethanol. This corrosive mixture can cause engine stoppage.

To prevent engine stoppage, it is important to keep water from accumulating in the tank in the first place. This can be achieved by using high-quality fuel additives, purchasing quality fuel from trusted sources, and regularly checking fuel filters and fuel tanks for sediment and water. It is also important to keep up with manufacturer-recommended preventative maintenance schedules.

Additionally, it is recommended to never use ethanol gasoline that is over 90 days old, as ethanol shortens the shelf life of gas, and old gas is more likely to absorb water and cause problems. Keeping up with maintenance schedules, such as changing fuel filters and cleaning the carburetor, can also help limit the sludge build-up attributed to ethanol.

Ethanol dissolves fiberglass fuel tanks, fuel filters, and carburetors

Ethanol can cause issues in boat engines, especially those that sit unused for long periods. This is because ethanol is an alcohol, which is corrosive to certain parts in older fuel systems. It is also hygroscopic, meaning it attracts water. When water gets into the fuel during a fill-up or from condensation, it can mix with the ethanol, creating a chemical reaction that causes rust, corrosion, and sticky varnish that can wreak havoc in fuel systems, especially carburetors.

Ethanol can also cause rubber parts and fuel lines to dry out, harden, and deteriorate prematurely. This includes gaskets, O-rings, and fuel lines, which can become clogged and cause fuel delivery problems. In addition, ethanol can attack gasket materials, fuel pumps, and rubber components in carburetors, dissolving them and causing engine damage.

To prevent these issues, it is recommended to run boat engines regularly, at least once a week, and to keep fuel tanks full or at least 3/4 full to prevent condensation. Fuel stabilizers can also be added to the fuel to help prevent ethanol-related issues.

It is worth noting that underground fiberglass fuel tanks and piping have been compatible with up to 100% ethanol for over 40 years. However, older engines and fuel systems may still be vulnerable to damage from ethanol-blended fuels.

Ethanol is a solvent that cleans sludge while dissolving polymers

Ethanol is a solvent that can cause significant damage to boat engines. It is known to dissolve polymers and sludge, which can cause issues in the engine. When ethanol-blended fuel is added to a fuel system that previously used non-ethanol gasoline, the ethanol dissolves and loosens deposits in the tank and fuel system. This can lead to phase separation, resulting in a layer of ethanol and water at the bottom of the fuel tank. This layer is a corrosive mixture that can cause engine problems and repairs.

Ethanol's ability to dissolve polymers is due to its similar intermolecular forces to water. Polyethylene glycol (PEG) and crown ethers, for example, have better solubility in ethanol because it can align along the polymer backbone. Methyl and ethyl cellulose are also freely soluble in ethanol. On the other hand, polymers with ethyl groups dangling along the hydrocarbon chain, such as poly(1,2-butylene glycol) (PBG), have reduced solubility in water due to the grouping.

When it comes to sludge, ethanol's solvent properties can lead to the formation of a brown slurry that clogs filters and critical engine parts. This slurry is a result of the chemical reaction between ethanol and MTBE, an oxygenate previously used in gasoline. The slurry has a gel-like consistency and can plug jets, foul injectors, and cause lean operating conditions, potentially leading to serious engine damage.

To minimise these issues, it is recommended to keep water out of the fuel system and use fuel additives to help clean deposits. Additionally, completely filling the tank with ethanol-blended fuel can help absorb any water present and reduce the risk of phase separation. Regular maintenance and following the manufacturer's recommendations are also crucial to prevent engine damage caused by ethanol.

Ethanol's long-term effects on marine engines

Ethanol is a pure plant-based alcohol that is both volatile and flammable. It is often made from corn, but can also be made from sugar beets, straw, wood chips, and sugar cane. It is used as an additive to fuel, to reduce hydrocarbon emissions that cause air pollution.

E10, the most common ethanol-gas blend, indicates a 10% ethanol, 90% gas ratio. Higher blends like E15 (15% ethanol, 85% gas) are also available. While E10 is generally fine for cars, it can cause issues for boats. This is because boats are often unused for long periods, and their vented fuel systems allow moisture to enter the gas tank. As ethanol is alcohol-based, it absorbs this moisture, which can cause havoc in a combustion engine.

The water in the tank causes a process called phase separation, where the gas rises to the top, and an ethanol/water blend sinks to the bottom. When this combusts, it can cause engine damage. Ethanol is also a potent solvent, which can wear down rubber hoses and plastic parts. It can also cause other parts to become brittle and break.

Boat manufacturers suggest using non-ethanol gasoline when possible, and thankfully, many marinas carry ethanol-free gasoline. If you have to use an ethanol blend, never use anything beyond E10, and be sure to use a high-quality marine fuel-water separator filter in your boat's gas line.

The long-term effects of ethanol on marine engines can be mitigated by following the above advice. However, it is important to note that ethanol shortens the shelf life of gas, and old gas is likely to absorb water and cause issues. It is also recommended to keep up with maintenance and address any repetitive performance issues immediately.

Ethanol-based fuels are not environmentally friendly

Secondly, ethanol fuel contributes to the problem of food scarcity. The challenge of growing enough crops to meet the demands of ethanol production is significant, and some argue, insurmountable. According to some authorities, producing enough biofuels to enable their widespread adoption could mean converting most of the world's remaining forests and open spaces into farmland—a sacrifice few would be willing to make. For example, replacing only 5% of the US's diesel consumption with biodiesel would require diverting approximately 60% of today's soy crops to biodiesel production.

Thirdly, ethanol-based fuels can cause engine damage, particularly in boats. This is because ethanol is a water-based product, and any water in the engine can cause rust. It can also attack gasket materials, fuel lines, fuel tanks, fuel pumps, and rubber components in carburetors.

Finally, ethanol-based fuels have been linked to declining bee populations, with potentially catastrophic implications for many other high-value agricultural crops that depend on bees for pollination.

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