E10/E15 octane difference?

[xgmad]

I've been using I believe 84 octane marine gas from shell from 2 years ago in my Stihl leafblower I bought a year ago.

I can hear it "brrring" which doesn't sound right, seems like its pinging.

Will mixing water with 94 octane fuel from the pump and then separating it (since the ethanol will be almost absorbed in the water)
at least keep a high enough octane? Or is the ethanol detrimental to the octane to the fuel?

 

[ctechbob]

@GoldDot40 has mentioned that at least in this area of the country, our REC90 (Non-Ethanol 'Recreational' fuel) is simply the base for 93 Octane pump gas, so 94 without ethanol assuming it is E10 should be around the same area.

Personally, I would run regular pump gas and then before I put the equipment away for the winter either run some E0 into it or drain it.

 

[kschachn]

I've been using I believe 84 octane marine gas from shell from 2 years ago in my Stihl leafblower I bought a year ago.

I can hear it "brrring" which doesn't sound right, seems like its pinging.

Will mixing water with 94 octane fuel from the pump and then separating it (since the ethanol will be almost absorbed in the water)
at least keep a high enough octane? Or is the ethanol detrimental to the octane to the fuel?

Ethanol increases the octane rating of gasoline.

 

[Danno]

Ethanol increases the octane rating of gasoline.

All things being equal, however, lower octane gasoline would be mixed with ethanol to achieve the target octane level.
Example, blenders could use 77 octane gasoline, bring in 10% ethanol at 100 octane giving a blend of 87 octane at the pump.

 

[Kestas]

You lose octane when you remove the ethanol.

 

[kschachn]

All things being equal, however, lower octane gasoline would be mixed with ethanol to achieve the target octane level.
Example, blenders could use 77 octane gasoline, bring in 10% ethanol at 100 octane giving a blend of 87 octane at the pump.

Yes, I was only going on what the OP wrote.

 

[Chris142]

Most of my stuff requires 89 or higher. Why would you run 84 and where do they sell it ? Lowest I see is 87.

 

[Barkleymut]

Was going to ask the same question, I've seen 85 octane once before. But 99% of stations here have 87, 89, and a higher which is usually 91 or 92 octane.

 

[MParr]

If you don’t use much 2 stroke fuel, just buy the canned pre-mixed stuff.

 

[kschachn]

One might guess the OP meant to type 94. I doubt "marine gas" would be 84 octane since low octane fuels are generally used only at high altitudes.

 

[xgmad]

One might guess the OP meant to type 94. I doubt "marine gas" would be 84 octane since low octane fuels are generally used only at high altitudes.

No, I'm being dead serious the shell marine station has 84 octane marine.

 

[kschachn]

No, I'm being dead serious the shell marine station has 84 octane marine.

So what does your leaf blower owner’s manual say is a minimum octane rating for fuel?

 

[kschachn]

No, I'm being dead serious the shell marine station has 84 octane marine.

What marina is selling Shell 84 octane gasoline?

 

[xgmad]

So what does your leaf blower owner’s manual say is a minimum octane rating for fuel?

94 octane

 

[Zaedock]

Stihl typically recommends 89 as a minimum.

You want to mix water in your gas and then "separate it" and run it in a Stihl piece of equipment? Jeebus.

 

[kschachn]

94 octane

That must be a weird one then, all the owner's manuals I saw online said 89 with one that said 90. What model is this?

 

[kschachn]

Stihl typically recommends 89 as a minimum.

You want to mix water in your gas and then "separate it" and run it in a Stihl piece of equipment? Jeebus.

It’s a good thing I don’t own this brand since the best I can do in my area is 93 octane.

 

[BMW Dom]

It’s a good thing I don’t own this brand since the best I can do in my area is 93 octane.

I feel like it is 89 in the manual

 

[wag123]

No, I'm being dead serious the shell marine station has 84 octane marine.

They either marked the pump wrong or you read it wrong. All of the E0 gas around here is 89 octane. That is what the marinas are selling.
Most OPE machines will run fine on 87 octane gas because their compression ratio is so low that they don't need a higher octane gas. The only exceptions that I am aware of are a small handful of professional high performance (high compression ratio) chainsaws. The reason that Echo (and other brands) has recommended 89 octane for many years is because they wanted you to get a higher level of detergent additives that the higher octane gas supposedly has. Echo engines would run on as low as 84 octane as this is all that used to be available in other parts of the world. This came directly from Echo's chief engineer (a VERY colorful German gentleman), I heard him say this myself at an advanced service seminar/school that I attended many years ago.

 

[GoldDot40]

To achieve 87E10, the CBOB is 84 octane + 10% of 111 octane ethanol to achieve 87 where I am.

Premium is 90 octane CBOB + 10% 111 octane ethanol to achieve 93.

Mid grade is 60% 84 CBOB, 30% 90 CBOB and 10% ethanol...blended as it's loaded.