Octane rating question

I know the saw manufacturers recommend 89 octane but the only 89 or 93 rated in my area in 10% alcohol which I refuse to run. My bulk tank here is 87 but no alcohol.
Am I hurting anything beside performance running the lower octane? I use only Stihl Ultra synthetic oil mix.
My closest 93 octane would be a 30 mile drive. I could get a five gallon container at a time but don't want to mix that much at once and have fuel go stale.

 

Your saws say to use 89 octane? All of the ones I've seen are made to run on 87, and that's e10 87 octane.

 

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I'll check again but I'm fairly sure that's what I read.

 

Went back and checked.All manuals recommend 89 and no more than 10 percent ethanol.

 

The lower the octane the more power. Octane inhibits burn for use in higher compression ratio engines. Saws even ported are around 8.5:1 so 87 is fine.

 

Do you have an airport nearby?

 

No,it's even farther.

 

I ran 87 ethanol mix for years with no problems. Not sure about VA but here if you read the tag on the pump it says "may contain up to 10% ethanol". 89 octane is the recommended octane for Stihl saws.

 

I have never run low octane fuel Jonsered recommended 90 octane or better for years I see so many saws ruined with 87 in my area I would never run it in any small engine but the fuel blends change in different areas I have test kits for ethanol and have had 10 to 14 percent in my area I myself use tru fuel because I have found it makes all my saws run /start better and all my saws have different mix ratios (old Hommies to new husky/jonsered) also I have always used synthetic oils and premium fuel but this topic always starts a lively debate on both sides of the fence just use what works for you JB

 

I do run non E 90 octane in my saws now that it is available here. I ran the 87 back in the day when I was young,dumb and poor.

 

That is the same thing I did back in my younger, dumber days. All of my small engines now only get the 93 octane non-E gas. My car is the only thing I put E gas in. At the pumps, the non-E gas is labeled as recreational gas.

 

I run 87/89 (lowest available) pump gas in all my saws, ported and not. It’s not eth free. I keep them run occasionally and use a premium oil. Not one issue in all my years. Saws are stored in my basement.

 

Lotta folk don’t smell what you’re puttin down. I get it and agree 100% with your post.
My bil will argue to his death that every gasoline engine he owns runs better on 91+. I gave up.

 

Just a FYI Jason. The rutters just north of dillsburg has non e gas now.

 

I run 91 or 93. I always go for non ethanol fuels as I was sick of the carb issues on my weedeater. I have had no issues, and I run my stuff pretty hard.

Good luck!

 

Have you ever actually tested it for eth? I watched a show where a guy went to multiple stations that sell the e-free and they all had it in their gas. When questioned the shops all blamed it on the suppliers stating they told them it was e-free, basically passing the buck.

 

I have only bought it once. Stihl working on those 3 gallons. Probably should test it considering the price.

 

87 is fine for any small two-stroke engine like a chainsaw. I believe the compression ratio only gets up to 8:1 or so. What I’ve noticed is that, if you aren’t 100% certain that the fuel is Efree, I would use the freshest fuel available. And that is usually in the 87 pump. In some states, premium 93 is ethanol free, but not in others. I believe that’s where a lot of the confusion comes from. Be careful running oxygenated fuels like 100LL in an M Tronic or auto tune saw. The electronics may not be able to richen the mixture enough to make up for the added oxygen mixed with the fuel

 

The one here on lake are routinely tested and only pumps I trust

 

You will not hurt performance by running with lower octane.

I run the cheapest e-free I can find. I get it from a station that sells a lot of it, so hopefully is fresh too.