Aviation fuel for chainsaws?????

[Jack Mincey]

With all the worry over alcohol in our gas that we use for chainsaws got me to thinking of a source that is alcohol free. I know of a few people that run Aviation fuel in their old hot rods since it is higher octane than what one can buy at a station. I'm pretty sure it is alcohol free as well. My question is the higher octane a bad thing for our chainsaws or not? I can drive to our local airport in ten minutes, but it is a hour and a half drive to the closest station that has alcohol free gas. Price isn't really a big problem with chainsaw gas since most of us only use a small amount over a years time. Jack

[Josh Bowman]

Jack, for my little motors and boat, I try to use gas that is alcohol free. They claim the little rubber parts fair better without alcohol. I just get it at any local gas station that advertises as such.

[John Coloccia]

Avgas is leaded.

[Curt Harms]

The most commonly available AvGas is 100LL (100 Octane low lead) I think -not certain- that octane is measured differently in AvGas than MoGas and AvGas is higher. Low Lead is not No Lead, I don't know if that would cause a problem or not. I don't use a chain saw often, maybe once or twice a year so when I'm done I drain the fuel tank then start it and run it 'til it quits. That way the fuel system is dry. I've seen no corrosion issues so far doing this.

[David Reed]

Higher octane fuels are fine for spark ignited engines as it is designed to function in higher compression engines lowering the risk of pre-ignition and ping, which can damage an engine. Can't imagine any problems burning this fuel in a two cycle engine.

[Jason Roehl]

All that a higher octane rating does is reduce the propensity of preignition/detonation/spark knock/compression ignition. In practice, what that means is that an engine that is built with a higher compression ratio (or forced induction) needs the higher octane rated fuels to prevent preignition. A typical car/pickup engine might be 8 or 9:1 compression ratio, a supercharged or turbo-charged engine would be more in the 6 to 7:1 range, and a high-compression engine (like a motorcycle) would be in the 10 to 11:1 range.

I've been running my Husqy on pump gas for the 9ish years I've had it, with no problems, nor any regard for whether the gas contained any alcohol. One thing I have done religiously is use the Husqy 2-cycle oil. I don't even drain the gas or run it out and still have no problems firing it up months later.

[Curt Harms]

Higher octane fuels are fine for spark ignited engines as it is designed to function in higher compression engines lowering the risk of pre-ignition and ping, which can damage an engine. Can't imagine any problems burning this fuel in a two cycle engine.

As I think about it, I can think of one potential problem. MoGas is formulated differently in winter & summer so vapor pressure is different, MoGas in the winter vaporizes easier at low temperatures. AvGas formulation does not change with the seasons. I wonder if getting a chainsaw started with AvGas would be a real exercise on a cold winter day. I do know that starting an aircraft piston engine below about 40o F without preheat is not recommended but there are other factors at work there. Dunno, never tried it.

[Matt Meiser]

If you don't use it that much why not just buy the premixed quarts sold for small engines? Auto parts stores and lawn and garden equipment stores sell it.

[Hayes Rutherford]

I try to use av gas in motors that tend to do a lot of sitting around. Since aircraft can't tolerate the problems associated with fuel containing alcohol such as fuel separation, deterioration of seals, vapor locking, etc. why have the problems in my sawmill, rototiller, seldom used off road motorcycle, etc.? (even though they can't fall out of the sky)

[Paul Williams]

Many folks flying older single engine airplanes not designed for the 100 LL aviation gas has switched to car gas. The switch greatly reduces plug fouling caused by the lead in av gas. If you can not find 80 octane av gas I would stick to car gas.

[george wilson]

Aviation gas does not go bad when stored for long periods like regular gas does.

[Steve Peterson]

I have heard that gas from the dock at a marina is alcohol free. It probably costs about $6-7 per gallon.

Steve

[Kyle Iwamoto]

My Stihl saw manuals say to NOT run premium gas, 89 octane or LOWER. Running ethanol is not a problem, if you mix 1 gallon or less, use it up or dump (environmentally soundly) it after a few months. Dump your gas from the tank if you aren't going to use the saw right away. Start the saw and run all the gas from the fuel lines and carb.
I cannot see a huge advantage in running avgas, breathing all that lead seems bad to me.:eek:

[Rob Price]

261603



261604

I buy this from the big box store $5-6 a can I think.

[jared herbert]

I see the mention of dumping gas/oil mix when it get too old as you dont want to use it in the chainsaw, weedeater, etc. I never dump it, just put it in my car or pickup. The small amount of oil that is in a quart or two of gas, when mixed in a full tank of gas in the car will not cause a problem. No need to dump something that does not need to be. Jared

[Ronald Blue]

Higher octane can actually reduce performance. This is because it is less volatile and burns at a controlled rate. The downside of that is it may not complete it's burn until the piston is already past the optimum range in the power stroke for power production. It may increase exhaust temperature because the gases are still burning on the way out. If it doesn't recommend a higher octane fuel then you might be disappointed in it's performance. High octane works in high compression engines because it is less likely to detonate prematurely and even if it does it isn't as significant as low octane would be. It produces a more controlled burn and in an engine designed for it potentially slightly more power.

[Dennis Nagle]

I was a timber cutter in the mt hood national forest for years and ran all my saws on pump regular 5 days a week 50 weeks a year without issue. Modern saws are designed for modern fuels.

[Matt Meiser]

Someone running a saw every day would be less likely to see issues than those of us who use them occasionally as the fuel would always be fresh.

[Dennis Nagle]

Now that I am using them only occasionally, my 15A year old Stihl 056 still runs strong.

[Jack Mincey]

I thought this would be an interesting question. Thanks for all the replay's. I have four saws, a weed eater, a leave blower, and a hedge trimmer that I use two cycle mixed oil in. I have always used Husky oil in my mix and have never had an issue. Had one old mcCulloch saw set for more than 3 years under a mobile home in Georgia we have for a deer hunting camp without being cranked. It took a few minutes to get it cranked after sitting so long with gas in it and the carb, but it cranked and ran fine for me when I needed it and was still running when I gave it to one of my students a few years ago. I do feel that using a high grade of oil for the mixture is imperative for best results. I did a little surfing on the net after posting my question today and found a station about 20 minutes from my home that carries ethanol free high test. The family that own the station are even friends of mine. Just because I've never had an issue with my gas doesn't mean I want in the future so I will start to use the ethanol free for my small engines. I use around 6 gallons each year so it stays fairly fresh. Thanks for all the replies, Jack

[Bob Bergstrom]

Over on one of the arborist sites the chainsaw guys will run av gas or pure gas only in their saws. I have two friends who run chainsaw mills and both have holed the piston using regular ethanol gas. Pre-ignition can be quite prevalent with all the stress of milling big logs. If nothing else is available, premium gas gas with ethanol has more cleaners and detergents with the higher octane. I use premium ethanol gas and add a little sea foam to each jug of mix. Sea foam is a great product to keep them running clean.

[Matt Meiser]

Just because I've never had an issue with my gas doesn't mean I want in the future

That's my thought. My Stihl dealer tried to talk me out of buying a case of the premixed fuel with my new trimmer because it was so expensive, but in the same conversation told me about how many carbs they replace due to corrosion. Husky's oil may have an ethanol treatment--I know Stihl's does (at least the grey cans.)

[Bob Bergstrom]

Those older Stihls and others are much more tolerant of crud in the fuels. In order to satisfy the environmentalists and others the newer carbs are finally metered when it comes to carburetors. They will clog up much quicker than the old trusty saws.

[Charles Wiggins]

With all the worry over alcohol in our gas that we use for chainsaws got me to thinking of a source that is alcohol free. I know of a few people that run Aviation fuel in their old hot rods since it is higher octane than what one can buy at a station. I'm pretty sure it is alcohol free as well. My question is the higher octane a bad thing for our chainsaws or not? I can drive to our local airport in ten minutes, but it is a hour and a half drive to the closest station that has alcohol free gas. Price isn't really a big problem with chainsaw gas since most of us only use a small amount over a years time. Jack

Never thought about AvGas. I found a station about 25 minutes south in Chesnee, SC that sells ethanol free regular. It's usually about the same price as E10 regular here at home. I have a 5 gallon gas can that I take down and fill when it gets low. I put STA-BIL Fuel Stabilizer (http://www.goldeagle.com/brands/stabil/products.aspx#stabil) in it at the time I fill it. I use it in all my small engines including when I mix more fuel for my chain saw.

You can look for sources at Pure-Gas.org (http://pure-gas.org/index.jsp?stateprov=NC). There's a station in Sylva that is supposed to have 93 octane, and a couple of places in Bryson City.

[Philip Duffy]

Zero engine problems since I went to AVGAS. Get it at the local airport and it costs a bit more but the chainsaw and lawnmower love it! P.

[Philip Duffy]

Switched to AVGAS 100 a year + ago and the lawn mower and chainsaw love it! No more starting problems and they run with full power. Just a few pennies more per gallon and its worth it, by a whole bunch, not to have engine problems.

[Ralph Lindberg]

I've had the chance to talk with a Stil factory rep about gas.
Absolutely never, ever, ever run E15 in your chainsaw (the shop I take my Husky to says the same thing). That appears to be the universal recommendation from every small-engine (including mower) on the market. He stated it would be better to get alcohol free gas then the regular gas/alcohol blend.
He also recommends 89 octane or "mid grade", he strongly recommended against 85.
What goes "bad" in today's "gas" is the various additives put in gas.
Both people also recommend never keeping gas past 90 days, even with fuel stabilizers.
Oh ya, use a good stabilizer.

[Tom Winship]

That's a good idea, Jared. I like that one a whole lot better than paying $5-$6 per can for the mix. (Almost $25/gallon)

[Ron Rutter]

I always thought the old av gas was 80-87 ?? Ron.

[Curt Harms]

I always thought the old av gas was 80-87 ?? Ron.

It was, dyed red. I don't know if it can still be found or not. There were a couple STCs to run older engines that didn't like 100LL due to lead fouling on MoGas. A stipulation of the STC was no alcohol so any airport selling mogas for airplanes will be alcohol free. I was never involved with those engines so don't really know the current state of that market. I do know there's a fair bit of effort going into finding a replacement for 100LL. The EPA has been after the aviation industry to become lead-free for years, and sourcing the tetraethyl lead additive is not getting easier. The AvGas business outside N. America is a tiny fraction of the fuels business and it's expensive to service due to AvGas having lead and requiring special handling as a result.

[Jason Roehl]

http://www.swiftenterprises.com/index.html (No affiliation, other than the owners of Swift Enterprises were clients of mine a few years ago).

Check the link from that page to Swift Fuels--they're working on a replacement for 100LL. I don't know what the current status of it is, but I know when I worked for the owners in '08, they were running it in a aviation turboprop engine (I think) on the ground with excellent results. Don't know if it's seen air time yet, though, or what the economic feasibility of its production is.

[Dennis Nagle]

This is a very interesting conversation. To add to the mix (pun intended) I call three old timber cutters out in Oregon that I use to work with and are still in the business. I also called one in Montana about this topic. They are all running the big new Stihls with 36" or longer bars. To a person, they all just go to the gas station and fill up the cans with regular. This has been going on since I got out of the business and before. They all follow the standard of three years on a saw, then sell it to a chord wood cutter. None of them had any issues with their saws that might even remotely be related to gas.

Then I called Sonny Meiric who owns Dick's logging supplies in Estacada OR. He is the guy in that area that everyone buys their saws from and takes their saw to for repair. He said that they might get a burned piston once a year, but it is always a matter of to lean an oil mixture. Anyway, just a little impromptu field research.

I am so glad I called all these guys. I considered them good friends while I work out there and from these conversations, I am going back to visit this summer.

[Curt Harms]

Something for those interested in the state of 'NextGen' AvGas. Written partially in the finest gov't bureaucratese:

http://www.faa.gov/news/safety_briefing/2013/media/MayJune2013.pdf

start on page 13 of the .pdf

[Hilel Salomon]

Those folks who say they have no problem with regular ethanol laced gas, usually run their equipment frequently. I use high octane ethanol free gas and have more power on my chainsaws and weedeaters. If you can't get ethanol gas, keep your equipment full!!! (It used to be the opposite) and run them for ten minutes at least once a month, and change the gas/oil mix every 6-8 weeks. Sea foam and the gas oil with additives are also helpful. Every repair shop I have dealt with is loaded with equipment in need of new carburetors because of ethanol. It is a farce which only helps the giant corn growing conglomerates and carburetor manufacturers. Telling us that ethanol is an energy saving policy is a total myth.

[Dennis Nagle]

That is true Hilel, they run them day in and day out.