(My boat sits for mo.'s but I have Sta-Bil in it.)
More specific internet wiki: Scary stuff.
Gasoline containing ethanol has become the new standard for fuel, and it presents a new set of challenges and work for classic car owners. You’ve got to be vigilant now to ensure a good running engine and prevent damage to your cherished car.
What’s the problem, you ask?
Ethanol, made from corn or grain, is added to gasoline to oxygenate it, replacing the older additive, MTBE. Names for gasoline mixed with ethanol include E10, gasohol, corn fuel, alcohol fuel, and reformulated or renewable fuel.
The key problem is that ethanol absorbs water from the atmosphere. In fact, fuel with 10 percent ethanol absorbs up to 50 times more water than standard gasoline. Older gas tanks found in many classic cars vent to the atmosphere, increasing the likelihood that moisture will be absorbed into the gas tank at a rapid pace.
The end result of water in the fuel is phase separation. The fuel separates into two distinct layers: a thick layer of gasoline mixed with a little ethanol on top, and a thinner layer on the bottom consisting of water mixed with most of the ethanol. And it doesn’t take much water for this to happen–phase separation occurs in a gallon of 10 percent ethanol blend with just 3.8 teaspoons of water.
Fuel Phase Separation Problems
What happens to your car and it’s performance when water causes fuel phase separation?
Reduced fuel longevity: A gasoline/ethanol blend absorbs water until it triggers phase separation. The blend has a 90-day product life in a closed tank, but lasts just 30 to 45 days in a vented tank often found in classic cars. With 10 percent ethanol blends, owners are supposed to replace the fuel in vented tanks about once a month by driving or draining, taking into consideration the humidity in the atmosphere and temperatures.
Lower fuel octane: The ethanol in a gasoline blend provides some of the octane rating. When phase separation occurs, the octane rating of the remaining fuel can drop by as much as three points.
Poor engine performance:The fuel pump could easily pick up a slug of the water/ethanol slurry at the bottom of the tank, interrupting the flow of gas to the engine. This will cause the engine to miss, run rough and possibly stall altogether.
