J.J.

When I was at the shop the other day, i walked into a conversation one of the guys was having with a customer regarding ethanol in gasoline.

Apparantly, the ethanol in pump gas attracts moisture, which will in time (if the gas is not burned regularly), corrode needle valves, valve seats, gaskets, and o-rings. They have (supposedly) seen, first-hand, carbs on new(er) bikes that looked "like they were 10 years old" as a result of this. Fuel injected engines also are NOT affected by this, but obviously we all have at least one carbed vehicle! The solution the guy said was fuel stablilizer if the bike is sitting for any length of time.

This story was confirmed for me today by an article in this months issue (!) of RoadBike magazine, including the part about stabilizer being a possible fix. Anyone know anything else about this?

PJay

Well, I do know a little about methanol, because I have road raced machines on methanol and gasoline/methanol mixtures for many years. I supect that ethanol will show the same problems, just not quite as badly or as fast as methanol. These are just my observations, as I am not a fuel expert; it would be interesting to hear from one.

You will get exactly the sort of corrosion described, particularly if the machine is left standing. The only solutions are either to run the machine all the time or to drain the fuel system between uses.

NB wanna rust out a steel tank? - leave alcohol sitting in it.

Methanol in particular will also attack many plastics and rubber compounds, of which there are lots in carburetion systems and injection systems, too. It is fair to say that by and large, the newer the system, the more resistant it will be in my experience.

Nanotech

Even ethanol will hurt certain hoses and aluminum tanks. Our university has done corrosion studies for converting a mini-indy car with a Honda 600 to ethanol, and a few things were bad enough to merit change or anodizing. That engine though is FI, so I don't know the full extent of damage to carbs. If it were that big of a deal I'm sure more people here or elsewhere would be noticing it....

Corona Hawk

What is their definition of "sitting for any length of time"? My Hawk will sit anywhere from 3 to 10 days. I am fortunate to have a station that does not have to add ethanol, but whenever I have to get gas in the city I have no choice but to get the Ethanol treated gas.

PJay

You're looking at weeks not days; definitely, I would say, a problem if you are likely to leave it standing more than a month.

I have had it happen - the bottom one-third of the needles on one of my classic racing Hondas disappeared altogether one year when I forgot to drain the carbs after the last race of the season. The fuel was mixed methanol and race gas, which separate out.

99Hawk

I found this fuel info on a Mercury Marine web site: (Some good info)
http://www.mercurymarine.com/ethanol




"..... If significant amounts of water are present in a fuel tank with gasoline that contains ethanol, the water will be drawn into the fuel until the saturation point is reached for the three-component mixture of water + gasoline + ethanol. Beyond this level of water, phase separation could cause most of the ethanol and water to separate from the bulk fuel and drop to the bottom of the tank, leaving gasoline with a significantly reduced level of ethanol in the upper phase (see Figure 1 below). If the lower phase of water and ethanol is large enough to reach the fuel inlet, it could be pumped directly to the engine and cause significant problems. Even if the ethanol water phase at the bottom of the tank is not drawn into the fuel inlet, the reduced ethanol level of the fuel reduces the octane rating by as much as 3 octane numbers, which could result in engine problems.
The level at which phase separation can occur is determined by a number of variables, including the amount of ethanol, the composition of the fuel, the temperature of the environment and the presence of contaminants. It is very important (A) that the system is inspected for significant quantities of water in the tank before using gasoline with ethanol and (B) to limit exposure of the fuel tank to excess water. If phase separation has occurred, it is necessary to completely remove all free water from the system and replace the fuel before continuing operation. Otherwise, engine problems could occur. ....."

(figure 1)




Is an additive available that can prevent phase separation?
There is no practical additive that can prevent phase separation from occurring. The only practical solution is to keep water from accumulating in the tank in the first place.


Are there any additives that can allow the phase-separated mixture to remix when added to the fuel tank?
No, the only way to avoid further problems is to remove the water, dispose of the depleted fuel, clean the tank and start with a fresh, dry load of fuel.

shayne

Honda Australia have recently stated they do not recommend ethanol fuels being used in any bikes. As stated above it is corrosive stuff, and I don't use it.

I haven't tested it in the Honda and don't intent to, but I did try some as an experiment in my injected Suzuki, and the engine did not run as well as it does on standard unleaded.

jschmidt

Ethanol is the main ingredient in Sta-Bil.

PJay

I had the brainwave of looking in my VTR owner's handbook. Sure enough , to paraphrase: "Do not run methanol, and keep ethanol below 10%". (I do not know if handbooks are the same for all markets.)

I refuse to keep the ethanol below 10% in my Scotch, even with water.