09-01-2008, 03:57 PM #1
Ethanol In The Fuel - Part 2 (Water)
As mentioned in part one of this study, ethanol is horrendous stuff. On further studying, this is the pwc owner’s worst nightmare. Have you ever wondered how out of nowhere your fuel tank has accumulated so much water? Is it at the pumps or did it come from condensation due to low fuel level? Well both are good answers to this question but there’s more to it then what you would think. Because ethanol is an alcohol additive called ethyl alcohol, it actually is classed as a solvent. An example of a solvent would be paint thinner or more closely related…gas line antifreeze. But, this solvent has some very unfriendly hidden characteristics. Ethyl alcohol is a hydroscopic solvent which means it absorbs water.
For those of us that are familiar with traditional gasoline, water and fuel separate like a bad marriage, but the water will look like small beads in the tank or carburetor under most normal conditions. Occasionally water will also collect and form into a large stretched out bead, if there is enough density for the water to overcome the oil-like properties of traditional fuel. Have you ever had a little bit of fuel back-log up the filler spout and get all over the ski? Well splash some water on it and it will bead off like a nice wax job but will feel slippery and oily. With ethanol, this is not the case. Ethanol will absorb the water and clean-up will be a breeze, no oily film and quick evaporation.
How does this tie into the water in your tank? Condensation only occurs when warm air meets colder air. Water droplets will form when cold air forces warm air to condense bringing humidity closer to any surface. This means larger accumulations of water can be taken out of the condensation theory to a relatively large point. As for the pumps, the tanks are as we know underground. Anything 6 feet and below ground naturally will be cool and damp much like a basement without a dehumidifier. This is a prime starting point for condensation build-up. But normally the water remains in the bottom right? What about when the tanker trucks stop in to replenish the fuel station’s supply? When they dump the new fuel in to the tanks, it stirs up the water and gets caught in the pumps when they’re running. Water in the tanks will take about 5 hours to settle because it now has all this new supply of ethanol to mix into. This is why fuel stations have testing meters that show how high the water levels are in the tanks. The best they can do is have a return tanker come in and vacuum out what it can for return to be reformulated and have the water separated.
Because of ethanol’s properties to absorb water, eventually it will get heavier and absorb all it can. At this point, the heavier weight of the water filled ethanol will drop down the bottom of the tank and the lighter fuel will stay on top. This is called phase separation and when phase separation begins, it falls into a domino effect. The ethanol that is heavy with water will try to pass enough water onto more ethanol until a weight balance has occurred. At this point you will notice a separate layer of water filled ethanol in the bottom of the tank while the rest of lighter fuel remains as the top layer.
Depending on the conditions, up to 80% of the ethanol will separate from the fuel and fall to the bottom layer. As little as 50mL (1.7oz) of water in a 38,000 liter (10,038.5 gallon) tank can start phase separation and phase separated fuel can not be reintroduced into the fuel with such things as water remover or gas-line antifreeze. It has to be drained out and your ski will need a thorough tank and fuel system cleaning. To make matters worse, when this alcohol separates from the rest of the fuel, your octane rating plummets and you are now running much less than 87 octane. Keep in mind that 87 rated fuel has at least 10% ethanol in it…if you remove 80% of that 10% ethanol, you are left with 1.74% ethanol making your octane rating 80.04
On top of this ability to absorb water it is also a good cleaner much like a degreaser. When you mix a degreaser with oil, be it in a 2-stroke or 4, the oil thins out considerably and now you are left with a “drier” running piston. This along with an alcohol that wants to hang onto water means bad news for a pwc engine. Additionally, other related issues with ethanol are:
-extremely poor shelf life (30 days max.)
-unstable flashpoint for combustion
-rapid degradation of fibreglass and plastics
-non-compatibility with cork gaskets and sealants
-the "cleaning" ability releases fine metals (anywhere in the fuel system that metal components can be found) into particles which can pass through filters
As a last addition, when in the first year of my small engines apprenticeship, we had a visit by the Stihl Limitted service rep. He spoke of the new and upcoming regulations regarding ethanol. He then named off a list of fuel stations which were already using it and said, "If anyone whom has purchased a chainsaw and filled it with fuel from any of these stations using ethanol blended fuel and not premium, Stihl will not warranty the engine". Here are a couple of links to support this.
Thanks for taking the time to read up. If you haven't seen part one, you might like it as well.
Last edited by Schwarzenegger; 09-01-2008 at 11:12 PM.
09-01-2008, 07:24 PM #2
We have been using ethanol in our gas up here in Minnesota for over 10 years now.
Even the 93 I put in my RXP has always had it. Never had a problem with the RXP or any small engine for that matter.
Having said that though, I always put seafoam in the last tank of the season
09-01-2008, 08:27 PM #3
Actually ethanol blending in RFG fuels has only been mandatory since 2003. Although it was around before then it was very uncommon because the base fuel which was also the cheapest to produce was MTBE based fuel. The U.S. relies on the California State emissions regulations as the foundation source for all emissions regulations nation wide. It was California Gov. Davis that pushed the date up one more year from it's proposed date of 2002 to 2003. In Canada the Ethanol Fuel Act passed in 2002. Also, your RXP is fuel injected so your ski was designed around this fuel to run on it. Why this is, was also mentioned in part one of the article http://www.greenhulk.net/forums/showthread.php?t=71886
But the purpose of this article is not to create arguement about how long it has been on the market or what engines aren't having much of or any affect by it. It is simply to inform people about the severity of what it can and has been documented to do in the small engine world. As a former 10 year small engine technician by profession, I have seen the damages and hardships caused by it which led to posting the info supplied. If you have had good luck with it then that's great dude, I'm sure hundreds of thousands of people have...but this offers a little insight to any fuel related problems people may have and had no answers. Thanks for reading about it though, it's good to see the article is being read.
Last edited by Schwarzenegger; 09-01-2008 at 11:18 PM.
09-02-2008, 02:01 PM #4
My point is that the ethanol additive is NOW a reality for almost if not all of us, but in Minnesota we have been using ethanol for over 10 years instead of MTBE. There is fewer and fewer places to find just 100% petrol and not a mix of some sort.
At first everybody feared that this ethanol would wreck small engines. Yep there were problems, but the problems have diminished drammatically since the "mix" was introduced.
09-02-2008, 04:17 PM #5
Yeah the engine destruction issues with it have cleared up somewhat. I think it's because of fuel injection phasing out carburetors. I just noticed your signature haha!! CLASSIC dude! I love Caddy Shack haha. Anyway, thanks for the input and keep that ski buffed and creamed
09-02-2008, 04:50 PM #6
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