Coop marked gas with ethanol.

[Roberth]

Sunoco article:
Are premium gasolines better?

"87-octane fuels are less refined and contain more unstable hydrocarbon compounds. As the months pass during storage, these unstable components react to form gums, varnishes and lower-octane hydrocarbons. As a result, the octane can decrease within 3 months for 87-octane fuels, especially when stored under less-than-ideal conditions.

“ Top Tier, 93-octane fuels sold at stations such as Chevron, Costco and others, are more refined and so contain hydrocarbons that remain stable. These stable hydrocarbons will last two to three times longer than those in 87-octane fuel. Even with proper storage, 87-octane gas can start to degrade in three months; 93-octane fuel should last closer to 9 months before degradation is detectable. High octane fuels also contain higher concentrations of detergents and other additives that help reduce carbon deposits and keep engine components clean. Keep in mind that even 93-octane fuels are still susceptible to octane loss and vapor pressure decreases due to butane evaporation over long periods of time.”

So, other than the added cost, is there a downside to filling your tank with high-octane gas?

“Filling up with premium even when you don’t need the octane will help to clean the engine systems better than 87 octane. Premium gasoline also ages better. No need for additional stabilizers or other off-the-shelf additives.”

The biggest downside I read about for higher octane fuels is my Yamaha 300 is rated for 89 octane. Reportedly higher than that a cause pre detonation at higher rpm leading to motor damage. That’s in the manual for the motor

 

[TheNootkaRose]

Once carbs/injectors are severely gummed up, there isn't many
solutions except to take apart and clean.
However using seafoam certainly helps prevent it.
It works for me anyway.

Do you run Seafoam Marine Pro or just the regular red label Seafoam?
Thanks

 

[Explorer682]

Hi All, what are your opinions on running the coop marked gas that now has up to 10% ethanol? Thats the same ethanol content as regular.
View attachment 103228


Now that's its got ethanol, I've started to add fuel stabilizer to the marked gas now, plus seafoam. I don't like it, but What else can I do... the only ethanol free gas now is chevron 94 and I'm not going to run that $$$.

Ethanol is going to be hardest on the little jets in the 9.9 kicker, plug em up. And will generally absorb water.

Is this ethanol change due to some government regulation ?


You could choose to save 7 cents and just run regular in that instance, since it has the same 10% ethanol content. I don't think outboards need the higher octane.

Yamaha Fuel Stabilizer and Conditioner Plus , primary purpose is to offset the ethanol so it’s supposed to be better than the Ring Free ( for higher hour motors )

 

[Jonnywwdb]

just got a reply back from mid-island coop. marked premium and premium is ethanol free until they're forced to change.

not sure who they would be buying it from. skeptical