Michigan Muskie Alliance

Is it here? Do stations have to post it on their pumps? Does it affect 2 strokes differently than 4's?

I haven't seen any gasohol around here in the Lansing area...

I have seen MANY pumps in Michigan with the 10% ethanol sticker, I don't know but I am assuming they do have to post it. It reportedly makes up about half the gas sold in Michigan. It should not affect the combustion in any type of engine. The concern with ethanol is damaging rubber (hoses, gaskets), which is NOT a problem at 10% concentration, and eroding pre-1990s fiberglass (the gas tank), which IS a problem at 10% for that older fiberglass. The real concern is moisture in the fuel- ethanol binds water up and can cause separation- best bet is to burn it up quickly (fish a lot)and keep it fresh. Use fuel stabilizer as a precaution for that if its going to sit around

Almost all stations on this side of the state have had ethanol for quite some time. Lots of info at boatus.com
http://my.boatus.com/forum/forum_topics ... D=142&PN=1 and there might even be a thread in here somewhere if you do a search. Keep up with your routine maintenance & don't ignore symptoms. We have a newer Merc. and haven't had any problems. It is garage kept & we do use stabilizer during storage.

I put the motors on the boat today. Getting ansy with the sunshine. I was surprised to find my gas tank was full. It sat in the shed for 4 months now topped off. 3.5 gallons and I used Stabil last fall, I have used it since day one. Should it be okay? Is there a way to see if it has separated? I could dump it into the mower can if need be. Last year the Honda fired right up. Was ethanol here then?

Fin-

The issue with old fuel is primarily varnish which we all know is nasty and plugs things up. The ethanol appears to be as, if not more, stable than the alkanes that make up gasoline. What is lost during the winter is the octane rating of the overall fuel. What does this mean tou you??? If you go out and run your boat hard in hot conditions you may experience some pre-igniton due to octane loss. Most fuel will smell weird due to the addition of sta-bil this is completely normal. I recommend and do this myself, store your tanks full- atmospheric air is the enemy, the more contact area the faster the decay. Run your boat at moderate speeds on that first tank of fuel, full acceleration is fine but try to cruise at 3/4 throttle or less. Once that is gone fill with fresh fuel and use as normal.

Kevin

Yes Kevin, that's true; the high-volatility components of the gasoline mixture will be lost first, and everything you said is correct. Varnish results when some of the additives (detergents, lubricants, anti-oxidants, and even dyes) either decompose or precipitate out as the mixture's composition changes.

On the other hand, I believe modern fuel systems are designed not to vent vapors like older systems did, and since he added stabilizer, he should be OK.

The downside of mixes containing methanol or ethanol are, like Duke said before, that they can be bad for some materials in older systems (all modern ones should be compatible) AND they can scavenge water from the atmosphere and mix it in with your gasoline ("dry gas" additives are alcohols and this is what they do to water in the bottom of a tank, btw) and make it perform badly if it absorbs a lot of water.

Like Kevin said, go ahead and use it, but don't horse around too much.

Chemi-

The issue of octane rating loss is one that I am not crystal clear on, I know that when fuel sits with stabilizer it does not varnish but it will still lose its octane rating. I have not been able to find anyone who can explain it to me chemically? Is it an issue of the straight chains losing Hydrogen and double bonding?? Or a degradation down to smaller molecules like pentane and butane? The good thing is that since ethanol rates betwenn 105 and 120~ it seems to negate a bit of that loss. The issue with the two strokes is the higher compression ratio and the higher absolute head pressure generated in that type of system (hemisperical head with no valving). Thus the better operation with higher octane, the big problem we see in the spring is the occurence of cold seizure. When people are operating on low octane fuel with an extremely low flashpoint the pre-ignition causes rapid overheating of the piston face. This can lead to geometric distortion of the piston faster than the cylinder resulting in piston to cylinder contact and subsequent compression/performance loss. This is REAL common in chainsaws even the newer ones so FYI to all reading.

Kevin

Actually, octane rating is a complicated issue.

Modern gasolines are very complex mixtures which are blended differently from region-to-region (MI gets a different blend from Denver, because of the higher altitude in Denver, and different from Fla, because of the different temperatures) and from season-to-season. MI gets different blends in summer and winter, for example. In summer, you want a blend with low-volatility components that won't evaporate away too easily or detonate prematurely in your engine. In winter, you WANT more high-volatility components to facilitate cold starting and easy vaporization, for example. If he filled his boat in the summer, and then tried to use it in cold weather, he might not get the performance he expects... even if the gas hasn't changed chemically.

"Octane rating" is essentially a measure of how rapidly a fuel mixture burns. Higher octane gasolines actually burn MORE SLOWLY and EVENLY than low octane fuels. This allows them to be used in high-performance, high-compression-ratio engines without detonating and causing "spark knock". This is actually the opposite of what most people think!

Some of the first components which are "lost" when fuel ages are the additives, some of which are "combustion modifiers" (just like the old-fashioned tetraethyl lead in "leaded" gasolines) which slow combustion down, thus increasing the octane rating. They usually aren't "lost" in the sense they evaporate away; they decompose chemically into something else which is no longer an effective octane booster. And yes, alcohols are octane boosters, in this sense, slowing combustion.

The alkanes and other hydrocarbons which are the main components in gasoline are relatively stable and don't react or decompose much, not in a few month's time, anyway.


Doe that help a bit?

I see.... That is always the unclear part is what exactly comprises an "additive package" is it anything like the Colonels "secret recipe"??

I have been trying to find the perfect solution of fuel to run in my stroker engine and have experimented with various concoctions which have ultimately not worked all that well. What worked awesome was E85 but according to the guys at Chrysler any older unit with metal components (ferrous based) in the fuel system WILL experience failure due to corrosion. THis makes sense form a water carrying standpoint but does not make sense chemically from the known behaviors of alcohol, ethanol in particular. I want to use it because at a 70/30 blend ratio I can increase my octane significantly at a lower cost than dump in booster and it runs great. Any thoughts on the claim of excess corrosion? I would just run it and see what happens but I dont want to be the guy who finds out the hard way. Also the increased flow rduced efficacy of alcohol has already been addressed via bigger injectors so leaning is not an issue.
Kevin

Alcohol is an excellent fuel, but it contains less energy per unit volume than gasoline, so you need to use more per mile, and you're already aware of that. Also, E85 has an octane rating of ~100-105, and in order to make best use of it, the engine needs to have a high compression-ratio, just like your stroker! Poifect!

As for whether the extra moisture in the ethanol will be bad for YOUR engine, I can't judge. I don't want you blaming me for your rusted-out stroker! What engine/year is it, btw?

Its not that exciting as far as cars go... It is in my 95 jeep, the I-6 engine which starts as a 242ci and ends up as a 275ci 4.6 liter. Returns are fair going from ~205CHP to ~290CHP with 340FT/LB. So in that light unit it is wicked, the problem as with all strokers is heat and pre-ignition. The CR is around 9.3:1 so pump premium is okay in cool weather but I need about 96 octane to keep it under control in the warm temps. That is why I love the E85 but cant get a definitive answer about component damage

It has taken a while to get all the other parametes under control, 21% larger injectors two heat range cooler plugs retard the timing etc- finally have it dialed I just want to find the best fuel setup.

Kevin

Have you seen this? Looks like '95 engines are right on the bubble...