High Octane Fuels in OPE

[Finz]

I'm fairly sure that my Echo ope's (chain saw, blower, trimmer) will run on 87 or 89 octane

1. Why, then, does the Echo or Tru Fuel containers make such a big deal about their having 93 octane?

2. From what I've read, Echo 2-cycle oil is about as Good as you're going to get but for infrequent residential use, is it worth the extra couple of dollars per container as compard to Tru Fuel?

I'm starting to use these canned fuels as I can't get ethanol-free fuel locally and I want to see if I can tell any difference using these products vs my own mix

Thoughts?

 

[exranger06]

Echo specifies 89 octane or higher for their equipment. I have 4 Echo machines, and all of them specify 89 octane. Why Echo specifies 89 octane? No idea. But, it's only 10 cents more than 87 octane, so I play it safe and use 89.

I use E10 pump gas with Stihl synthetic oil. I never have any problems with it. I'm not willing to spend 7x as much for something without ethanol when E10 doesn't cause any problems to begin with.

 

[Finz]

I agree.. $28-$30/gallon is a lot but I'm sick of cleaning carbs and such at the onset of the next season. I doubt I'll do it for an entire season or a can or 2. But I didn't realize Echo calls for 89... That might be a part of the reason... Igniting a little too early?

But with regard to high octane, is there any benefit at all to using 93 vs 89? I don't know enough about the mechanics but, from what little I do know, I don't see how or why 93 would be any better. In fact, an argument could be made against using too high an octane, no? Something about the amount of power or punch behind the combustion?

What made you decide to go with Stihl oil?

 

[PhilsSmallEngine]

The theory goes that because the higher octane burns completely at a higher temperature, it's an advantage to use it in higher temperature running air cooled equipment. Does it work? Sometimes. My 2 cycle equipment gets treated 93 octane and I can tweak them more to run better. Not so much in raw power, but in throttle response. My 4 cycles just get treated standard grade 87 or 89 and call it a day. 1/10 of a HP in larger 4 cycles means nothing, but it can in smaller 2 cycles. I also use 93 incase there is ethanol separation and loss of octane as a result.

Stihl oil is fantastic at cleaning carbon deposits. I've never seen an oil so successful at that. I still run Amsoil since I can use less oil and achieve great performance, but I still give them a treatment of Stihl 50:1 every 2-3 5 gallon cans.

The volume of spongy and failed fuel lines and carburetors since e10 was required here gives me pause to the claim ethanol is not damaging.

 

[Finz]

Go
Originally Posted By: PhilsSmallEngine
The theory goes that because the higher octane burns completely at a higher temperature, it's an advantage to use it in higher temperature running air cooled equipment. Does it work? Sometimes. My 2 cycle equipment gets treated 93 octane and I can tweak them more to run better. Not so much in raw power, but in throttle response. My 4 cycles just get treated standard grade 87 or 89 and call it a day. 1/10 of a HP in larger 4 cycles means nothing, but it can in smaller 2 cycles. I also use 93 incase there is ethanol separation and loss of octane as a result.

Stihl oil is fantastic at cleaning carbon deposits. I've never seen an oil so successful at that. I still run Amsoil since I can use less oil and achieve great performance, but I still give them a treatment of Stihl 50:1 every 2-3 5 gallon cans.

The volume of spongy and failed fuel lines and carburetors since e10 was required here gives me pause to the claim ethanol is not damaging.


Well that's good to know about the stihl oil... You use less of the amsoil? so more like 60:1 or less? How did you determine that a mixture other than 50:1 with Amsoil was adequate?

Funny you should mention the throttle response... Cleaned and put new plug and fuel filter in the blower and used the Echo canned fuel... Just enough to get it to run for about 10 minutes or so. There was never any middle ground with the throttle - either full tilt or slow idle. Noticed today about 5 minutes into run that it would actually stay running at differing speeds... That might have been the case the first year, but so long ago I can't be sure

Well, I'll be.... That's something

 

[Donald]

For me its not the cost per gallon rather its the cost per season. I use maybe 2 QTs of premix/yr and it runs fine with little or no maint. So I spend $10 a year on 2 cycle fuel.

Actually I bought 5 QTs of Craftsman 50:1 premix on clearance ($1.25/QT) as they moved those out to carry only 40:1 which is what all their stuff uses.

 

[Finz]

That's a good point... I'll track the costs seasonally and compare. No question the leaf blower uses the most

 

[boraticus]

From my experience and what I've read about two cycle engines, higher octane fuel is neither required nor beneficial.

Most two cycle engines run at lower compression ratios. Higher octane does nothing to improve performance in low compression engines.

It might provide some illusion of improved performance, but, in reality, nothing other than that. Save your money and run regular fuel in low compression engines.

 

[Hokiefyd]

Two cycle Lawn-Boys recommend at least 89 octane fuel as well. So do Husqvarna and Stihl. It seems to me that there's got to be something to every major maker of two cycle engines recommending a higher grade of fuel.

 

[BigCahuna]

Have they changed emission output standards for OPE, that might somehow require higher octane? All I've ever used in my stuff is regular gas that I add my fuel treatment to it when I fill the can. I don't have any special ritual that I do at the end of the season, and everything starts and runs fine in the spring. I can honestly say I haven't experienced any issue with ethanol gas, ever.,,,

 

[lars11]

Well, do you suffer badly from engine knocking in your OPE???

Boraticus is at the point. High "octane" rating is a non issue in OPEs.
No, I think there's a misunderstanding that octane somehow equals "quality" or "power" which is not the case per se.

But I suppose that some vendors put more work into more expensive fuels for say higher end engines and therefore you may get higher quality fuel with less water and debris in it when you buy gas with higher octane rating. Hence the mix-up.

If I could pick, I would use high quality fuel, clean and non cracked, formulated with a low octane rating for my OPE. If any effect, lower octane rating -might- improve ignition.. Might..

 

[1 FMF]

for some manufacturers they don't make a good piece of equipment to begin with so i see little reason in believing that everything in their owner's manual or what they recommend to be correct in the first place.

only valid reason i can think of to say use 89 vs 87 is that it's an air cooled engine and can run hot, so as a manufacturer to account for all operating conditions it's safer to say 89 vs 87. that's speculation on my part at best.
when using 2-cycle oil mixed in gas, more oil doesn't contribute to heat and power, it reduces combustion temps (otherwise running a 30:1 oil would run better than a 100:1 mix)
so for cases where you are using a high end 2-stroke oil that says mix at 100:1 vs the traditional 50:1 then I could see combustion temps being higher in hot conditions where a higher octane fuel might prevent detonation... maybe.
but i don't run my 2-stroke with high end synthetic oil at 100:1 or higher mix ratio looking for max power, i mix at 50:1 to 40:1 for protection and longevity and have always used 87 octane with no problems.

 

[Silverado12]

I have an old Lawn-Boy 2 stroker that runs smoother with high octane. I know it's not my imagination, so I'll keep using 92 in all my 2 and 4 stroke machines. They don't burn that much to worry about the extra cost of fuel for me.

 

[Srt20]

Originally Posted By: 1 FMF
for some manufacturers they don't make a good piece of equipment to begin with so i see little reason in believing that everything in their owner's manual or what they recommend to be correct in the first place.

only valid reason i can think of to say use 89 vs 87 is that it's an air cooled engine and can run hot, so as a manufacturer to account for all operating conditions it's safer to say 89 vs 87. that's speculation on my part at best.
when using 2-cycle oil mixed in gas, more oil doesn't contribute to heat and power, it reduces combustion temps (otherwise running a 30:1 oil would run better than a 100:1 mix)
so for cases where you are using a high end 2-stroke oil that says mix at 100:1 vs the traditional 50:1 then I could see combustion temps being higher in hot conditions where a higher octane fuel might prevent detonation... maybe.
but i don't run my 2-stroke with high end synthetic oil at 100:1 or higher mix ratio looking for max power, i mix at 50:1 to 40:1 for protection and longevity and have always used 87 octane with no problems.

More oil=more power peak hp is usually around 18.1
Oil is lubrication
Gas actually helps cool the engine before it is combusted.
Higher octane prevents detonation. If the engine calls for higher than 87, it's probably a little higher in compression.

 

[dlundblad]

Higher octane tends to have less than 10% ethanol IIRC. OPE engines don't seem to care about octane in general.

A station somewhat local to me sells ethanol free 91.. its a bit pricey, but for as much as I use its not big deal.

 

[bubbatime]

The reason they request 89 octane is that when you add oil to the fuel, the octane lowers. So that 89 octane now becomes 87 or 86 octane.

Add in the fact that most fuel now has ethanol in it. Ethanol degrades over time and is hydroscopic, meaning it absorbs water from the air and is capable of absorbing 100% of its weight in water. So technically, over time, a 10% ethanol blend fuel can absorb 10% water from the air and become a 80% gasoline, 10% ethanol, and 10% water mixture. Your 87 octane fuel has now become a 83 octane fuel.

That is the reason you run higher octane fuel in 2 cycle equipment.

 

[Finz]

Originally Posted By: bubbatime
The reason they request 89 octane is that when you add oil to the fuel, the octane lowers. So that 89 octane now becomes 87 or 86 octane.

Add in the fact that most fuel now has ethanol in it. Ethanol degrades over time and is hydroscopic, meaning it absorbs water from the air and is capable of absorbing 100% of its weight in water. So technically, over time, a 10% ethanol blend fuel can absorb 10% water from the air and become a 80% gasoline, 10% ethanol, and 10% water mixture. Your 87 octane fuel has now become a 83 octane fuel.

That is the reason you run higher octane fuel in 2 cycle equipment.


Very good info... Thank you!

 

[LX289]

The higher octane burns better in OPE IMO. I run the highest grade pump gas without ethanol or alcohol in my OPE. You will want the stuff with no ethanol because ethanol causes MAJOR problems in OPE with the carbs. The ethanol attracts the moisture...... which = bad things. I don't buy that canned stuff just because of the price but it might be more of a convenience thing for others.... If you can't get non-ethanol fuel than i would continue to use the canned stuff. The oils in the canned fuel are synthetics IIRC.