Fuelproof your engine

Prevent ethanol engine damage

The U.S. Environmental Protection Agency is currently considering a Clean Air Act waiver that would raise the allowable ethanol content of gasoline from 10 percent to 15 percent.

Ethanol-diluted gasoline can wreak havoc on marine engines and fuel systems. But if you educate yourself about ethanol and take the right steps to protect your boat, you can prevent most problems.

The main problems that ethanol poses stem from two properties:

Ethanol is hygroscopic, meaning it tends to absorb water.

Ethanol is a strong solvent.

Keep moisture at bay

When ethanol-diluted gasoline sits for a long time in a boat’s fuel tank, it absorbs moisture from the environment. If it absorbs enough moisture, the ethanol separates from the gas in a phenomenon called “phase separation.” If this straight ethanol-water mixture is sucked into the engine to be burned as fuel, it can cause performance problems and engine damage.

When storing a boat with ethanol in the tanks, keep the tanks at their normal full level to limit the amount of moisture-producing air in the tank and treat the fuel with a stabilizer to postpone the dreaded phase separation.

It’s also a good idea to install one or two water-separating fuel filters in the fuel line between the tank and the engine. Check these filters often for signs of water.

Protect engine components

As a solvent, ethanol literally eats away many rubbers and polymers that easily withstand a gasoline-only environment. It can even dissolve fiberglass resins and epoxy. The dissolved resins are deposited in the running engine, eventually destroying it. In addition, ethanol can eat away fuel delivery lines unless you replace them with an ethanol-compatible material.

Now here’s the good news: Many marinas carry gasoline that has not been diluted with ethanol. Be sure you know your state’s regulations regarding the use of non-blended gasoline before filling up.

Like it or not, ethanol in our fuel is a reality. But if you understand the problems that ethanol can cause, you can help your engine live a long, healthy life.