Ethanol-laced fuel has changed some of the rules for winterizing marine gasoline systems. When prepping a boat for winter storage, boat owners must now do all they can to avoid phase separation — a phenomenon in which ethanol combines with water and separates from gasoline, descending in a soupy goop to the bottom of the tank. While this can occur at any time, it is more likely to happen when gas is stored for long periods.
The simplest solution? Avoid using gasoline with ethanol, if possible. There are a few outlets that dispense ethanol-free gas (boatingmag.com/pure-gas), but there may not be one nearby. If you can’t avoid ethanol (as most of us cannot), make sure the fuel contains no more than 10 percent, known as E10. Let’s focus on how to prepare such gasoline and related components in an outboard boat for winter.
Tools and Supplies
Gasoline stabilizer such as ValvTect Ethanol Fuel Treatment
Six-gallon remote gas tank
TC-W3 two-stroke oil
Engine oil and oil filter (for four-stroke outboards)
New fuel filter elements
Filter wrenches (to remove oil and fuel filters)
Hex-head driver (for replacing hose clamps)
Large slotted screwdriver (to drain lower-unit lube)
Oil catcher to recycle old engine oil and gear lube ($19.95, oilfiltersonline.com)
Cleanup rags (to wipe up spilled fuel, oil or gear lube)
Avoid hose clamps with the narrower band widths. Instead, use clamps with half-inch band widths for a more secure connection and better seal.
For complete engine fogging, pull the spark plugs, spray fogging oil into each cylinder and turn the engine over (without starting the engine).