89 octane in 2-stroke?

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My new Echo trimmer calls for 89 octane fuel and explicitly says no more than 10% ethanol. No disputing that ethanol and small engines don't play nicely, but the 89 octane surprised me. Do I really need the 89? I usually just load up the big jerry cans with 87 when I'm putting gas in the car and mix up a gallon of 2-stroke gas for the snow blower or weed whacker.
 
2-cycle oil will drop the octane number by a point or two. I think Stihl is specifying min. 89 octane now. In a nutshell, engine knock is more likely to quickly damage a 2-stroke engine than a 4-stroke.
 
Originally Posted By: bubbatime
Premix fuel is $5 a can a Home Depot. It's the way to go if you don't use gallons of two stroke fuel a year.
+1
 
I use gallons per year. All sorts of chainsaws, trimmers, outboards, etc. Just regular and good oil for me. They have to live on pump fuel or they are out of here ...
 
My Echo trimmer is about four years old now, and it specifies 89 octane, and that's what I have been using. I buy the small pre-measured bottles of Stihl oil in the orange container to make a gallon at a time. Have not done any maintenance to it in the four year period, and it has been used by my brother and I to maintain about 3.5 acres of property.
 
Agreed on the oil mix lowering the octane slightly. Only problem I have with the pre-mixed stuff is the price. One quart lists for $5.96 at Home Depot. Gee, only $23.84 a gallon! Seems awfully pricey just because it's pre-mixed, ethanol-free, high octane, and has a long shelf life. Mixing myself still comes in about $3.50 a gallon with the oil and Sta-bil.
 
I just buy 91 octane for all my OPE and off road toys. Only the dirt bike and the chainsaw need 91 octane but for like $20/year difference in fuel cost, I don't have multiple grades of gas kicking around and I don't worry about running stuff hard. If I was putting $200/weekend into a boat then I would run the minimum octane needed.
 
For my husqvarna unit, and my small lot I buy about 2-3 cans of fuel per season, and we use it almost year round.

I buy the premix 2 stroke fuel from lowes. Trufuel is the brandname.

I believe the can says it is 91 octane fuel premixed with oil.

For 10-15 dollars a year in fuel, I would just stick with the canned stuff, and not risk gumming it up.

Especially in Texas when you have a long storage period for winter.

For my 4 stroke mower, I just use regular 87 gas, and do nothing but treat it during Texas winter which has been lasting about 2 weeks a year.
 
To answer your question, 89 isn't necessary but there is a marked difference in how modern 2-stroke equipment runs on it vs. regular. And with non-adjustable carburetors there's no way to tweak mixture to adjust for poorer fuel, etc.

Try it, you'll see the difference.
 
My Poulan leaf blower and Echo trimmer both run remarkably better on Shell/Phillips 66 93 octane. I use synthetic 2-stroke oil only. The spark plug in the 7 year old leaf blower is the OEM plug.
 
All of my air cooled OPE, 2 and 4 stroke, one or two cylinders call for 89 Octane. (I know, I actually read all the manuals.)

I don't know why the OP is surprised.
 
I've got an Echo saw that calls for non-ethanol 89, too. The only E0 I can find nearby is 87, and it runs fine on that. There's a station at a lake further away, and I think they have 90. I might try that.
 
I run 91 octane ethanol-free gas. I got tired of fixing stuff when I needed it. The first half gallon goes into my truck to flush any ethanol out of the pump hose.
 
Originally Posted By: Crispysea
I've got an Echo saw that calls for non-ethanol 89, too. The only E0 I can find nearby is 87, and it runs fine on that. There's a station at a lake further away, and I think they have 90. I might try that.

The manual says E0? Or does it say max E10?
 
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