Newbie gas comparison

drrpm said:

A lot of marinas only carry mid grade or premium gas. There are several gas stations in the Augusta Ga area that carry ethanol free gas and 2 near Clarks Hill AKA Thurmond lake. But to answer your question there is no difference in gas between marinas and the gas station other than price.

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Texasmark said:

I would like to run premium fuel in my engine but don't because I live in the country and country bumpkins usually use the cheapest fuel they can buy which means the premium just sits in the tank, and sits in the tank, and degenerates, and looses all the volatile ingredients that make the octane that it is advertised to be disappear, so why pay the premium price?

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smokingcrater said:

Octane goes UP as it ages... The components that raise octane are long chain hydrocarbons. They are less volatile and evaporate/break down slower than the more volatile short chain molecules. If you think about it, octane is a measure of how easy gas will ignite, the longer it sits around, the harder it becomes to light up, up to the point you can no longer light it at all.

Either way, higher octane in an engine not designed for it just means less power and more cost. Zero advantages in a typical marine engine.

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smokingcrater said:

Octane goes UP as it ages... The components that raise octane are long chain hydrocarbons. They are less volatile and evaporate/break down slower than the more volatile short chain molecules. If you think about it, octane is a measure of how easy gas will ignite, the longer it sits around, the harder it becomes to light up, up to the point you can no longer light it at all.

Either way, higher octane in an engine not designed for it just means less power and more cost. Zero advantages in a typical marine engine.

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Texasmark said:

Gotta disagree. If you have a low usage marina and sloppy hygiene, sir, there certainly is a difference between marina gas and road gas especially from a frequently used, name brand, service facility on the highway. I realize it all comes from the same place and additives are put in at the destination, depending upon the name on the Marquee, but that is not the final answer when it goes through your engine.

I would like to run premium fuel in my engine but don't because I live in the country and country bumpkins usually use the cheapest fuel they can buy which means the premium just sits in the tank, and sits in the tank, and degenerates, and looses all the volatile ingredients that make the octane that it is advertised to be disappear, so why pay the premium price?

Again, my 2c, worth what just what you paid for it.

Mark

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drrpm said:

A lot of marinas only carry mid grade or premium gas. There are several gas stations in the Augusta Ga area that carry ethanol free gas and 2 near Clarks Hill AKA Thurmond lake. But to answer your question there is no difference in gas between marinas and the gas station other than price.

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mpdive said:

Hi Mark. Just a question....Why would you want to run premium in your boat if it's not designed to unless that's what your manual says. The premium has a higher octane but has different combustion priciples because it's designed to run in different compression engines. The difference between the engines dictates the fuel used. If it's designed for mid grade the high octane does nothing for you except empty your wallet. Keep in mind the engine controls and timing are designed and set for the fuel used. I totally agree with you about the age of marina fuel. I have a few stations around Augusta Ga. that I use to stay away from the ethanol. Hope you have an extended boating season like we'll have here in South Carolina. Take care

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Texasmark said:

Simple question, simple answer: Because I (think I ) would recapture some of the octane I lost with E10, beins my engine was mfgr'd before the advent of such and it is a known fact that E10 doesn't have the BTU capacity that plain ole gasoline has, and around here that's all you can get at the "regular" grade pump...... so I loose some of my whoopie having to burn the environmentally friendly stuff.

But in reality, I have no idea as to whether or not I would get a boost with premium because I don't buy it for the reason stated. Won't go into the past, but in the past I figured it (premium) had a longer burn cycle than the lower octane and in a 2 cycle engine you have to get your BTU's in the first half of the piston stroke cause the last half is exhaust so you want a fast burning fuel....but I never proved that "wives tale????". Pure conjecture......butt could have merit.

Mark

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Texasmark said:

Simple question, simple answer: Because I (think I ) would recapture some of the octane I lost with E10

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mpdive said:

Yea I understand. Biggest propblem I have with the whole ethanol thing is that if you add regular fuel to e10 you drop the water suspension properties of the e10. For example if you have a half tank of e10 and add a half tank of regular, you now have e5. E10 can hold up to 4 teaspoons of water in suspension but the lower the E rating the less it will hold. The problem is that if you have half a tank of E10 that's old fuel or has absorbed moisture and is at it's saturation point, the addition of regular fuel under the right temp swing will allow the water and octane to drop out to the bottom of the tank. Pain in the *** but, you either stay with E10 or regular but avoid the mixing. At least some fuel stabilizers like Startron claim to stop and even reverse phase seperation. I run a water seperator and additives and try to use the fuel up so it's as fresh as possible. I wish they would just eliminate E10 so I could get corn for 10 ears for a buck again! Enjoy your holiday and be safe!

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oldjeep said:

Again, LOL. Must only happen in the south, we've had E10 for 20+ years and it doesn't do anything but clean all the crap out of your neglected dirty fuel system (and eat hoses that should have been replaced 20 years ago)

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