# aviation gas in chainsaw ok???



## six7bird (Jul 7, 2011)

can i run 100LL (low lead) aviation fuel in my chainsaw without problems? The stihl dealer here sells vp racing fuel for ten dollars a gallon he said it is 94 octane i can get the aviation fuel for six a gallon. i am thinking both have to be better than the ethenol mixed fuel from the gas station thanks


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## Stumpys Customs (Jul 7, 2011)

six7bird said:


> can i run 100LL (low lead) aviation fuel in my chainsaw without problems? The stihl dealer here sells vp racing fuel for ten dollars a gallon he said it is 94 octane i can get the aviation fuel for six a gallon. i am thinking both have to be better than the ethenol mixed fuel from the gas station thanks


 
SHouldn't be any problem at all, just make sure you retune it after the switch.


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## blsnelling (Jul 7, 2011)

Lots and lots of threads on this. Opinions are all over the place. I won't run AV gas.


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## Termite (Jul 7, 2011)

I do run 100ll av-gas and like it for the long shelf life. The last thing I do in the winter is run some in my boat motor.
I had a bad experience with racing gas. It caused the ring to stick in my Dolmar 401. I bought the saw new and the only fuel it saw until the ring stuck was racing gas. The consciences was the additives in the fuel.


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## oneoldbanjo (Jul 7, 2011)

*Avgas*

I ran Avgas for about a year in my equipment. It ran OK.....but not any better. It does have a long shelf life and when it evaporates it leaves nothing behind to gum anything up - but it runs too rich unless you retune the carb. I finally stopped running it as the trip to get Avgas is about 1.5 hours round trip.

Most recently I checked this site: Ethanol-free gas stations in the U.S. and Canada

I found a station nearby in Indiana that sells 90 octane gasoline without ethanol. Several of the places listed on the site no longer have ethanol free fuel - so you find one near you listed you will have to test the fuel to be sure.

Before I put my equipment away for an extended period I dump the fuel and then start it and let it idle until it stops. Then I put some Avgas 100LL mixed with the oil of my choice in the tank and restart the engine - then I stop the engine, dump the fuel in the tank back into my Avgas fuel can, and then let the engine idle again until it stops.

If you run Avgas - be sure to mark the cans so that no one accidently gives it to someone whose car has run out of gas. The lead will foul the catalytic converter.


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## Nitroman (Jul 8, 2011)

oneoldbanjo said:


> If you run Avgas - be sure to mark the cans so that no one accidently gives it to someone whose car has run out of gas. The lead will foul the catalytic converter.



It isn't the convertor so much, but the O2 sensors. This will cause your cars' comp to think it is running super lean and then you'll find out just how much your engine can chugalug gas. Think a 30mpg car going to 10mpg, for real.

If you have access to both race-gas and AVgas, just buy a gallon of each and mix it the way you'd normally do for your saw. Yes you have to touch up the carb but hell, everybody does that in that in the morning anyways. Find that big gnarly oak or cypress and cut some up with each fuel and see which one you thinks runs the best.


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## Mad Professor (Jul 8, 2011)

100LL is all I have used in my 2-strokes since the nerds in the Gooberment forced E10 or MBTE fuels on us.

Some saws run richer and need carb reset, some run just fine as they did with pre-E10 premium.


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## cujet (Jul 8, 2011)

100LL is an excellent fuel. It's consistent from batch to batch. So, once tuned, you are good to go. 

Here is something that may not matter to saw users. When GP 2 stroke bikes switched to unleaded, the crankshaft bearings (in particular the con rod big end) life was less than half. Failures became the "norm". It was eventually traced back to the lack of lead in the fuel. 

Since then, a few people have tracked 2 stroke engine life on leaded fuels and sure enough, they do last longer.


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## sachsmo (Jul 8, 2011)

The higher the octane rating the more resistant it is to detonation/pre-ignition. Higher octane burns slower. It is said that it will actually make your saw slower. This may well be the case, but the longer shelf life, resistance to detonation, and complete absence of ethenol makes it the fuel of choice for my saws. (110 leaded Sunoco) I do some milling with my bigger saws, and the piece of mind is worth the 2 or 3 bucks extra per gallon.

Ethenol is an oxegenated fuel, meaning it introduces more O2 which can make a saw run lean, lean is faster to a point, then you cross that line and it will melt down your saw. The old racers had a saying "lean is mean, but fat is where it's at" N20 works under the same principle, more O2, (lots more) kind of like forced induction. Thus you MUST add fuel (gas) to prevent leaning out to the point of destruction.

Good fresh pump gas, proper tuning, and good maintenance will suffice for most saws, but if you really push them, such as long rips through thick hardwoods. Why not buy a little insurance?


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## GASoline71 (Jul 8, 2011)

You cats that freak out over 10% ethanol make me LOL 

Also cats that run Av-gas, VP, and other stuff in a chainsaw make me LOL... 

89 to 92 octane (even with 10% ethanol) will be just fine for your ***. Just don't let it set for months on end in your equipment...

Meh... :msp_razz:

Gary


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## sachsmo (Jul 8, 2011)

GASoline71 said:


> You cats that freak out over 10% ethanol make me LOL
> 
> Also cats that run Av-gas, VP, and other stuff in a chainsaw make me LOL...
> 
> ...


 
Oh great wise one,

You have spoken, it must be the truth. What oil mixes the best with eth?


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## GASoline71 (Jul 8, 2011)

I actually agree with what you said genius... relax.

Gary


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## Tree Sling'r (Jul 8, 2011)

GASoline71 said:


> You cats that freak out over 10% ethanol make me LOL
> 
> Also cats that run Av-gas, VP, and other stuff in a chainsaw make me LOL...
> 
> ...



Hey bud, if I run diesel, what ratio should I mix it at? What brand of mix?


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## nmurph (Jul 8, 2011)

AV gas---no extra performance----actually diminishes somewhat---89-93 octane is sufficient for everything except modded saw running compression over 200psi

Ethanol--- no problem, but don't let it sit for months. Buy fuel in batches that will be used in less than 2 months--ethanol or not. Use a fuel stabilizer or two stroke mix with stabilizer added


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## GASoline71 (Jul 8, 2011)

If runnin' diesel you should mix with rendered bacon fat @ 77.361:1



Gary


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## Sprintcar (Jul 8, 2011)

If running diesel ya hav to run Gary Goo oil. Mix ratio is 1/1, smokes a wee tad but you can also put in the oil tank fer your bar and chain.


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## Sprintcar (Jul 8, 2011)

All joking aside you can run 100LL Aviation Grade Gasoline in your two stroke equipment if you want to spend the money. For that matter you can run any of the "High Performance" type gasolines however the difference you will see and feel is negligible in a stock or very mildly modified saw. 

If you are running a modified saw with very HIGH cylinder pressures, then racing gas or methanol is the way to go. I have attached several MSDS Sheets for various grades of gasoline. Please review the actual contents that make up the product.

View attachment 189934
View attachment 189935
View attachment 189936
View attachment 189937
View attachment 189938


As stated on this thread some folks swear by 100LL Aviation Gas and some think it's a load of crap, your saw, your choice.


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## MacLaren (Jul 8, 2011)

six7bird said:


> can i run 100LL (low lead) aviation fuel in my chainsaw without problems? The stihl dealer here sells vp racing fuel for ten dollars a gallon he said it is 94 octane i can get the aviation fuel for six a gallon. i am thinking both have to be better than the ethenol mixed fuel from the gas station thanks


 
From those two options, I would go with the VP94. As a matter of fact, thats what was recommended to me to run in my ported saws. 
However, I usually just run the Ethanol free 93.


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## cujet (Jul 8, 2011)

nmurph said:


> AV gas---no extra performance----actually diminishes somewhat---89-93 octane is sufficient for everything except modded saw running compression over 200psi
> 
> Ethanol--- no problem, but don't let it sit for months. Buy fuel in batches that will be used in less than 2 months--ethanol or not. Use a fuel stabilizer or two stroke mix with stabilizer added



It's true, and I forgot to mention that 100LL "may" result is a slight power loss and sligtly lower peak RPM. It's commonly thought to be a fuel engineered for low RPM engines. That may or may not be true. But, the higher octane does have a slower flame front. And, in a high RPM, 2 stroke, the exhaust port can easily be uncovered by the piston prior to the completion of combusion.


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## struggle (Jul 8, 2011)

I just finished my first five gallons of VP 110 and on the last gallon mix I only had enough to mix 50% ethonal free 87 octance with 50% vp 110.

I though the saws ran better with it blended like that. So that is my story and I am sticking with it.

I have seen it somehwere that is you run to high of actane it can actually hurt performance and run the saw hotter. 

If it is on the internet it has to be true


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## blsnelling (Jul 8, 2011)

struggle said:


> I just finished my first five gallons of VP 110 and on the last gallon mix I only had enough to mix 50% ethonal free 87 octance with 50% vp 110.
> 
> I though the saws ran better with it blended like that. So that is my story and I am sticking with it.
> 
> ...


 
Race fuel and pump gasoline are made of different chemical components. It's not just mixing 110 octane and 87 octane gasoline together. I wonder if there are any negative side effects to mixing the different kinds of fuels?

If anything, I would expect pump gasoline to run hotter than race fuel. The race fuel burns slower.


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## Banacanin (Jul 8, 2011)

Tree Sling'r said:


> Hey bud, if I run diesel, what ratio should I mix it at? What brand of mix?


 
the mix isn't as important as the diesel, try something in a number six fuel oil (bunker c), it should be self lubricating


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## Hillbilly1 (Jul 8, 2011)

To add to what Brad suggested -

I would too, since using these different fuels the saws are not designed for is far more likely to result in non-ideal stoichiometric conditions (carb tunes that are off), and the hottest burn of the fuel will be having the perfect air/fuel ratio. Stock saws. Since the saws are designed for pump gas 89 octane they will likely achieve the maximum thermal efficiency at that point, the hotter without mechanical damage or detonation the better. Well, I don't know "for sure" with the saws but damn sure automotive engines are designed that way. It's just fundamentals of internal combustion engines. 160deg t-stats, 170, 180, 195, 210 - the temperatures keep creeping up. Why? Max efficiency.

Further, burn rate itself is not always reliably indicated by the octane rating I don't believe - from octane rating the only thing one should infer is the fuel's resistance to detonation. Nothing more. There's a lot of other factors going on there depending on how and what is blended.


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## struggle (Jul 8, 2011)

I talked to the guys at the fuel place and both suggested that many other blend the fuel as well to lower over all octance rating. 

I am not saying it is right or wrong as it would be beyond me in the mecular build up of the different fuel packages and as to wether or not this could cause more problems. (spell check not working?)


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## CTYank (Jul 8, 2011)

Hillbilly1 said:


> To add to what Brad suggested -
> 
> I would too, since using these different fuels the saws are not designed for is far more likely to result in non-ideal stoichiometric conditions (carb tunes that are off), and the hottest burn of the fuel will be having the perfect air/fuel ratio. Stock saws. Since the saws are designed for pump gas 89 octane they will likely achieve the maximum thermal efficiency at that point, the hotter without mechanical damage or detonation the better. Well, I don't know "for sure" with the saws but damn sure automotive engines are designed that way. It's just fundamentals of internal combustion engines. 160deg t-stats, 170, 180, 195, 210 - the temperatures keep creeping up. Why? Max efficiency.
> 
> Further, burn rate itself is not always reliably indicated by the octane rating I don't believe - from octane rating the only thing one should infer is the fuel's resistance to detonation. Nothing more. There's a lot of other factors going on there depending on how and what is blended.


 
FWIW, 160 deg T-stats were to keep methanol-based anti-freeze from boiling off. The trend toward 210 deg was driven by emissions requirements- better fuel vaporization.

Compression ratios typical of road-legal engines and typical pump gas result in much more heat dissipation than with racing engines run on high-octane fuels. For a given power output. Mechanical efficiency-related.


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## komatsuvarna (Jul 8, 2011)

Ive ran 10% Ethanol fuel for 3+ years and never had a failur from it. Between chainsaws and cut off saws, I probably average 2 gallons a week, sometimes a little more. Just dont let it set in the saw for a long time and it will be fine.


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## MacLaren (Jul 8, 2011)

komatsuvarna said:


> Ive ran 10% Ethanol fuel for 3+ years and never had a failur from it. Between chainsaws and cut off saws, I probably average 2 gallons a week, sometimes a little more. Just dont let it set in the saw for a long time and it will be fine.


 
So, you really dont even have to add stabil? Just as long as you use the gas within a reasonable time?


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## mdavlee (Jul 8, 2011)

I've never run any AV gas but I have ran a tank of the Vp gas that paul had. I usually run 93 non ethanol when I can. If not I'll mix 1 gallon at a time of 93 with ethanol and dump it if it's not used within 2 weeks now.


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## nmurph (Jul 8, 2011)

MacLaren said:


> So, you really dont even have to add stabil? Just as long as you use the gas within a reasonable time?


 
I use Stihl Ultra oil. It has a stabilizer blended from the factory. I don't hesitate to use mix that is a couple of months old.


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## Hillbilly1 (Jul 8, 2011)

CTYank said:


> FWIW, 160 deg T-stats were to keep methanol-based anti-freeze from boiling off. The trend toward 210 deg was driven by *emissions requirements*- better fuel vaporization.
> 
> Compression ratios typical of road-legal engines and typical pump gas result in much more heat dissipation than with racing engines run on high-octane fuels. For a given power output. Mechanical efficiency-related.


 
The hotter you can keep an engine running within the limits modern metallurgy and lubes allow, the greater the efficiency and fuel economy, which is of course inseperable from emissions (particularly for those that consider CO2 an emission - topic for another discussion, much the same as those thinking ethanol is a great idea....). Raising the fuel economy is the biggest knob to turn toward lowering tailpipe emissions, by default. Better fuel vaporization would be a minor factor in the improvement, if any. Atomization and combustion turbulence is the name of that game ergo the higher pressure and direct injection systems.

Old managers shuttered the doors on boiler houses and kept ambient temperatures at 165F (even in the one I work in, back in the day), smothering all the workers for one reason - saving every last hunk of coal they could. Same goes for engines. Now we just get to 145F in the summer!

Aluminum heads - there's your heat dissipation. Enabling higher CR's and all that jazz as you stated.


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## Hillbilly1 (Jul 8, 2011)

Damn, sorry guys me and CTYank went way off the reservation.

Back to the topic at hand, run 93 octane with or without ethanol, store in cool and dry place out of sunlight in reasonably tight containers, use fuel stabilizer and or quality oil with it in it already, use up and repeat within a few months. Idle engines dry before storage, not after a long hard bucking cut or something like that, of course.

Ethanol although sucking most majorly, is not the bane of our existence it has been made out to be in all the over the counter saw shop discussions.


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## komatsuvarna (Jul 8, 2011)

MacLaren said:


> So, you really dont even have to add stabil? Just as long as you use the gas within a reasonable time?


 
nope. I run ultra and 93 shell V-power. I left it in my weed wacker all winter and it started up and ran fine in the spring.......but i try not to let it set in there that long if i remember it.


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## MacLaren (Jul 8, 2011)

komatsuvarna said:


> nope. I run ultra and 93 shell V-power. I left it in my weed wacker all winter and it started up and ran fine in the spring.......but i try not to let it set in there that long if i remember it.


 
Good deal.


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## oneoldbanjo (Jul 9, 2011)

GASoline71 said:


> You cats that freak out over 10% ethanol make me LOL
> 
> Also cats that run Av-gas, VP, and other stuff in a chainsaw make me LOL...
> 
> ...


 
Yep.....I will admit it.....I overworry the issue and go out of my way to avoid ethanol fuel. When I have used E10 and been conistent about keeping the fuel fresh I have never had any problems. The problem is that I have 25 acres to maintain by myself and a lot of equipment to help me out. I have 3 chainsaws, a log splitter, a Yardman push mower, a Kawasaki weedwacker with a brush blade, a Stihl weedwacker with a string head, a Toro snow blower, a Billy Goat mower for long grass, a DR walk behind brush mower, a Kees slicer for seeding the lawn, an engine driven lawn aerator, a Swisher 60" pull behind finish mower, an Exmark 52" walk behind mower, a Poulan leaf blower, a Mantis Tiller, a Generac generator, and a neighbor just gave me a Kawasaki gasoline hedge trimmer. It is hard to keep up with the maintenance of all this equipment - so using good fuel helps considerably to avoid any problems. I am able to buy 90 octane ethanol free fuel in a 55 gallon drum and I add Sta-bil and that much fuel lasts me about a year and stays fresh.

So far this year the only thing I have had to do to my equipment is run the fuel out of my snowblower and replace the fuel lines on my 12 year old Kawasaki trimmer. I have repaired 2 lawnmowers with dissolved diapragms, replaced the fuel lines on 1 leaf blower, replaced the diaphrams in 1 string trimmer, cleaned the carb on a tiller all for neighbors that used ethanol fuel and don't keep it fresh.

I keep about 1/2 gallon of 100LL Avgas in my generator fuel tank at all times so that I know it will start when I need it (I turn off the fuel and run the carb dry when I put it way - and when I am using the generator I will use ethanol fuel from the pump as I am using the fuel immediately). In all my other equipment I run ethanol free fuel with Sta-bil. I do scheduled maintenance on my equipment and occasionally they need something fixed - but I have never had any fuel related failures. The extra effort of getting good fuel seems to help me and gives me piece of mind - as I have seen what the ethanol fuel does to equipment that I fix for other people.


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## GASoline71 (Jul 9, 2011)

nmurph said:


> I use Stihl Ultra oil. It has a stabilizer blended from the factory. I don't hesitate to use mix that is a couple of months old.


 
Yup... same here. 

Gary


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## CTYank (Jul 9, 2011)

Hillbilly1 said:


> Damn, sorry guys me and CTYank went way off the reservation.
> 
> Back to the topic at hand, run 93 octane with or without ethanol, store in cool and dry place out of sunlight in reasonably tight containers, use fuel stabilizer and or quality oil with it in it already, use up and repeat within a few months. Idle engines dry before storage, not after a long hard bucking cut or something like that, of course.
> 
> Ethanol although sucking most majorly, is not the bane of our existence it has been made out to be in all the over the counter saw shop discussions.


 
"off the reservation"? Maybe you're thinking of Sarah? I don't go rogue.

All seriousness aside, I was simply trying to address some pretty obvious misconceptions in previous posts, one of which related to fuel octane rating.


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## Hillbilly1 (Jul 9, 2011)

CTYank said:


> "off the reservation"? Maybe you're thinking of Sarah? I don't go rogue.
> 
> All seriousness aside, I was simply trying to address some pretty obvious misconceptions in previous posts, one of which related to fuel octane rating.


 
I was more referring to myself. I burned down the teepee and ran over the hill, fell off the cliff, long ago. :hmm3grin2orange:


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