Chainsaw gas octane, what do you really need ??

Do U need , mid grade or premium, or is regular OK ????

My saws have been happy with mid grade ethonel free but at the last station fill up there was a sticker on the pump that said 10% ehtonel. I talked to the station owner and he told me they did it to stay competative with their prices. I also told him that he had lost me as a customer. A differant station up the road has regular pure no ethonel gas but at 25 cents more a gallon. So that's what my saws use now. I think regular is just fine as long as it is good pure regular. David.

The lower grade fuel really isn't good for your saws. The local Stihl dealer has an aviation license and he sells AvGas (ethanol-free 101 octane, I believe) but it's really salty (somewhere around 8 bucks a gallon). I have all older saws, most of them were rebuilt and customized by me. I run 89 or 92 in them, but I mix a tad more oil than others as well (around 40:1) to help the saw get a little extra lube due to the ethanol being in the gas now. I've not had any problems with my saws, but occasionally I DO get some of that AvGas and after a retune on the saw, what a HUGE difference in power.....honestly, it makes that big of a difference. Something to remember is when you run a better gas in your saw, you WILL have to retune it because most likely the saw will be running rich. Same goes when you run lesser gas in your saw, chances are you will have to richen the carb because of the lower octane rating. Something else to keep in mind, OPE was NEVER MEANT to be run with ethanol gas in it. It will do OK with the 10% fuels, but it will NOT live very long running 15% or higher.......Just some food for thought...

Thanks Scotty
Good Info.
I always mix the 50:1 oil quantity but use less than a gal of gas.
I don't have any of the newest saws , but are they also NOT meant to be run with ethanol gas in em ??

Ethanol gas is okay if you follow the rules:

- reputable gas seller
- less than 10% ethanol
- 90 octane or higher
- add quality 2-cycle mix (w/stabilizer) immediately
- don't mix more than you'll use in a couple/few months

I recommend a minimum 90 octane for saws because I have a couple saws that specify 90 or 91 minimum octane in their manuals. These days, I use 93 octane + Stihl Ultra for everything.

I made the switch just recently too, from running 87 octane regular 10% Etoh, to running 90 octane Etoh free. It costs about 65 cents more per gallon here, and there is only one place to get it in Ravenna about 12 miles away. I figure its worth the little bit extra, my saws seem to really like it! Like TreePointer, I have some saws that say to use it, so I'm just going to feed it to all of them.

I've run 87, 89, 93 with multiple oils mixed. Haven't found any combination that was mixed correctly (I've run 50:1 or leaner in all my equipment.) that didn't run the saws just fine. Husky and Stihl both say run 89 and that's because mixing the fuel with oil lowers the octane a bit. Running a higher octane fuel will not yield better power unless the saw is tuned to take advantage. Most of us do not play with the ignition timing on our saws.

In some areas, premium grade fuel (90+) is ethanol free still. That would make a positive difference in engine performance.

AvGas (Usually 100LL which works out to about 96 Octane using the RM/2 method auto fuel uses.) is a completely different formula than auto fuel, and ethanol free. It's no surprise so many report better performance running it. I don't run/recommend it because of the lead content (much higher than auto fuel ever was) and proximity to the exhaust fumes.

Fuel varies so much by region/season that what one person swears by may not make a difference for someone else in a different area.

Well ! I guess I will have to find out who is selling what kind of gas , around here, It's suppose to say the, ethanol % , on the pump, isn't it ??

While they don't tell you the actual percentage, the sticker should say something like "Contains up to 10% Ethanol"

I use premium gasoline myself with StaBil (red) added at the pump to keep the octane high. I spend the extra to get premium non-ethanol marine gas (only gas in Oregon that you can get w/o ethanol). I would use premium in all my 2-stroke engines regardless, as gas octane drops pretty fast with age, and octane also drops after adding premix oil to it. As an aside, Stihl designs their engines to be run on mid grade or better. They have also designed and re-tuned their current line of saws to run on American mid-grade ethanol E10 gasoline. Dolmar had some issues with their 5100 saws not being re-tuned for crappy American grade gasoline (German gas has far higher octane than US gas). They ran too lean here.

The real issue with running lower octane gas in a small 2-stroke engine is that it does not burn as evenly. Uneven burning and flaring at TDC causes uneven pressure on the piston, and that in turn can cause the piston to tilt slightly as a result (if a flare is not parallel to the centerline of the bearings). Over time this causes more wear on the piston skirt and cylinder. There is slightly more power in premium gas as compared to regular, but not that you would notice it. Also Avgas has lead in it, and I would not want to run a saw near me burning toxic tetraethyl lead. Non-leaded non-ethanol premium gas mixed with a good JASO rated air-cooled engine premix oil (non-marine) is all you really need to use to avoid any gas issues with 2-stroke chainsaw engines. Add gas stabilizer if the gas is going to be in there for more than a month. Some premix oils have stabilizer in them, some do not; I use Elf 100% synthetic motorcycle oil, and it does not. Also as someone mentioned above, re-tune your saws if you change gas grades or premix. I changed premix oil from dyno to synthetic several years ago and my saws all ran faster at WOT on the better 100% synthetic oil. I would highly recommend using 100% synthetic JASO FC or better oil in your saws (new or old), they will run better and have fewer problems running it.

who has ethanol free gas in ravenna? I;ve been all over the state for work and haven't seen one in almost a year now.


If you have to use ethanol fuel, only mix up a gallon or two at a time. The ethanol attacts moisture like no other. i would not personally use it after sitting more than 2weeks, 3 max. Also, Do not leave any ethanol fuel in ANYTHING. no chainsaws, mowers, weed eaters, snoblowers, etc. you will be replacing rotten fuel lines, and rebuilding plugged carbs. this new fuel sucks and is very hard on anything that has rubber, aluminum, brass, plastic (carbueretors, fuel lines, tanks,etc)

That is a federal standard sticker, but ethanol gas blending is regulated by state/province and regional laws. In Oregon E10 means 10% ethanol. Oregon used to have an option at the pump from 0 to about 6% for E10, but the greenies went wild here and maxed out the ethanol requirements to 10% on all gas sold in the state. The marine engines all instantly took a dive from water uptake by the ethanol, and so they backed off and allow marine premium 100% pure gas now. In Washington state E10 varies from 2% to 10%, depending, but you can get pure E0 gas there. In California, E10 used to means 6% ethanol, but as ethanol is cheaper than gas, many stations there are now at 10%. 6% is all that is really needed for oxygenating gas for winter months to improve air quality. It varies from state to state, region and/or by season as to what E10 is.

Here is a web site that lists gas stations that sell pure gasoline by state and province (two listed in Ravenna, OH):

http://pure-gas.org/

My 2-stroke saws, blowers and trimmers all survived the 10% ethanol gas mandate in very wet and soggy Oregon. You can use E10 and blend it with a good stabilizer, and it will stay fresh up to a year. I have torn down and modified several engines after using it for several years, and I cannot tell any difference. No phase separated gas, no fouled plugs, no rotten fuel lines, no dead carbs, etc. But I take care of my gas, I keep it dry, I add red StaBil at the pump before I load it into my truck, I tune my saws often, I use a top quality premix oil, and all that good stuff.

Now that said, I reverted to using E0 premium once it was made available here again. In marine engines, E10 is the kiss of death, even with StaBil green formula. A slosh of water in a gas tank and it is toast.

I run whatever the cheap stuff is. It's a damn chainsaw not a Lamborghini!

100LL would be rough on the lungs and I'm sure not healthy!

I dunno why but the fumes stick around for a while. I ran maybe a qt through my splitter when I ran out of reg gas (run 100LL in my race car).
Could smell the av gas for MANY tanks after!
Selling it for 8$ a gallon is crazy! Here it runs around 1.00-1.50$ more per gal than pump gas. There is a pay at the pump at the airport, just pull up and fill whatever.

Ravenna Oil on Lake Street. From you, Rt 76 to 44, north on 44 towards Ravenna, just outside of "Downtown" make a left (west) on Lake Street. Its just a good stones throw from that corner of Lake and Rt 44. Buckey over at "White's" told me there is a place on the east side of Alliance too but I didn't get the specifics about it.

When I bought my 026PRO the techs at the dealer insisted on using regular as high test could make the saw run hot.
That dealer was bought out by a nasty outfit that went out of business and there aren't too many stihl dealers around any more.
Last one I went to recommends 'whatever works'.
I always run regular, but have tried high test ( someone else's can group cutting) and could tell no difference.
None of my older saws run so haven't seen ethanol.
I think I get a little extra kick from the ethanol, I just don't like partially full cans lying around. I prefer my gas cans (and tanks) either empty or full and nothing in between. Seems to help with the ethanol / condensation woes.

Gee, if you were closer, I'd come and take those older non-running saws off your hands for you .

Nice link, thanks StihlHead!

And here it is again . . . the perennial ethanol question.

For the record . . . I've been running my two-stroker sleds for quite some time now with ethanol fuel and these sleds cost a heckuva lot more than any single chainsaw . . . maybe I didn't do it right, but on my last sled the engine was still solid and running great with over 10,000 miles on it (and I assume it's still running right now somewhere in New Brunswick, Canada). The key is to use the fuel stabilizers and not running it in a lot of the older equipment with older fittings, gaskets, hoses, etc.

Now to answer the original question and stay on track . . . the pat answer is to follow the manufacturer's suggestion. What most of us do is run the mid to high grade . . . but if for some reason you use the cheaper stuff to either save some money or because you forgot you will be fine . . . just don't put the bar oil in the gas tank and the gas in the bar oil tank . . . that will not work out so well.

With the ethanol fuel do you guys still have issues with fuel lines freezing up? My tractor that has a snowblower on it seems to collect a fair amount of moisture in the fuel and end up freezing in the float bowl of carb. Since adding in a splash of methanol with every fill I haven't had any trouble.

I run 89 in all my 2 stroke stuff, but in all honesty, the lower the ethanol content then the better it is.

Nope . . . from what I've read and seen ethanol acts a lot like an anti-freezing agent . . . much like dry gas which contains alcohol. In fact, some reports say you should not use dry gas.

I’m with nate and jake on this one – I always run the cheap stuff with 10% ethanol. Sometimes ‘cheap’ is 87 octane or sometimes 89. I make sure to get the ethanol as it helps boost the octane, clean the fuel system and acts as a natural gas line ‘dryer’ (ie, it’s basically like adding some HEET to each tank, as HEET is just overpriced alcohol, too)

I do mix gas with the recommended ratio of name brand 2-stroke oil…generally Huskvarna oil for my Husky saw, then that mix gets used in leaf blowers, weed eaters, etc. I don’t usually ‘winterize’ the saw – just fill with gas/bar oil and touch up the chain when I’m done cutting wood. I figure that way, it’s ready to go for the next wood cutting session – whether that happens to be a planned outing or a storm / other emergency.

All my stuff gets at least 10% ethanol, including jet skis, leaf blowers, weed eaters, chain saws, motorcycles, cars, etc. I've never noticed any deterioration, failure or other issues which would be attributed to the ethanol...actually the opposite - there is never any water or gunk in the bottom of the tanks and/or water separators. Average age of most of this stuff is 10+ years and still going strong.

Just to be clear . . . I try to go with the recommended fuel octane by the manufacturer . . . but I don't stay awake at night if I forget and use the cheaper stuff.

I also don't fear breaking down on the sled in the middle of nowhere on a cold January night . . . but I also do pre-season maintenance on my sled and for most of my small engines (lawn mower, ATV, splitter, sled, etc.) use Star Tron as a fuel stabilizer to reduce the chances of the fuel separating out.

I run 87 octane corn liquor "enriched" gas in everything.