Racing/High Octane/Aviation Fuel in Chainsaws?

[Hexa Fox]

First off please no one jump on me and call me a moron, I would appreciate it. Okay I really want this cleared up. I know very little about fuel except Gasoline can be used to get harsh chemicals off your fingers and Diesel Gels up when it gets cold. So I have a lot to learn to say the least.

A couple years ago or so I came here (I think) when I was having trouble with my MS 290 Farm Boss not starting at all. I came to find out that it was the crappy ethanol-free fuel the dealer directed me to use in it. I came to find out that the non-ethanol fuel was garbage in the saw. This was also due to us (Charles Town, WV) not having any high rated ethanol free fuel available. Plus I figured out that since no one ever uses it that it sits in the tank and degrades to be even worse. Therefore I was having major issues with my saw.

Long story short I took it under warranty to a real authorized Stihl Dealer and he told me he didn't care what anyone else told me. He then told me to buy the highest rated fuel I could find which is around 94 here around Charles Town, WV. This instantaneously resolved my issue and the saw has been starting right up. However this recently got me thinking and reading.

Is it okay to use any kind of Racing Fuel, Aviation Fuel, or other High End Fuel in Chainsaws? This has been a HUGE argument forever and everyone is back and forth. People say they burn cooler then they say that they burn hot. Then they say that it is all loggers use in their saws and others saw only if you want to blow up the small engine. Although it would seem that there are more people saying if you can afford it buy the Racing Fuel, Aviation Fuel, etc that it is the way to go. Just I really can not afford to have my saw explode in my hands or do damage to it overtime.

It is time for me to go get some new fuel and is why I have made this post. I am considering driving out to Summit Point Raceway and buying some Racing Fuel to try it out. Please give me your thoughts and advice. I can afford the fuel, especially if it will help my saw in the long run and give me a longer shelf life.

 

[windthrown]

I avoid racing fuel and I would never run Avgas in my stock chainsaws. Avgas has lead in it, and that is highly toxic at any level. Also 100 octane is a waste in a stock chainsaw designed and tuned to run 89/90 octane gas (US rated). The ignition and compression are set to run mid-grade US gas on most saws. You are better off with E0 non-ethanol gas, because ethanol picks up water over time. E10 will run OK, and if I had my choice between regular E0 gas and supreme E10 gas, I would probably run supreme E10, but with a good gas stabilizer in it. In any case, avoid using old gas in a saw. If you had a higher compression chainsaw, or a highly modified chainsaw with the timing advanced significantly, then higher octane racing gas might make sense. A stock MS290 is neither. I would save your money on the spendy racing gas and buy a brand name supreme E0 gas. Travel for it if you have to, I used to go up to WA state to get mine. Also use a high quality 100% synthetic premix oil with a JASO FC or FD rating and good gas stabilizer like StaBil, StarTron or SeaFoam.

I use E0 supreme 92 octane gas with StaBil red gas stabilizer in it. Reason being is that gas drops in octane fast and stabilizers will keep the octane value up for a year or two (depending on how much you add). If you buy 92 octane gas it is likely going to test out at about 90 by the time you get it into a gas can and add stabilizer to it. When you add premix oil to your gas you also lower the octane further by a few points (depends on the amount that you add, I use 45:1 gas/oil in my later model stock saws, and 40:1 in my older and modified saws).

My ex insists on using regular E10 gas in her MS290 saw. She says if it is good enough for the county work crews, it is good enough for her. I do not agree, but her 290 is still running strong after about 8 years of use. She uses fresh gas though with stabilizer and air-cooled premix oil (avoid generic and TCW-3 rated oil) in it and not stuff that has been sitting in a can down in the barn for who knows how long. She also keeps the saw tuned which is important so that you do not run it lean and burn up the engine.

 

[Hexa Fox]

Thanks for your reply windthrown. I use the top grade Stihl Ultra "Stabil" stuff they recommend. The ethanol free stuff made no difference what I did it was just garbage. I found this website a while back.
http://pure-gas.org/?stateprov=OR

You can look up the nearest places to you and I have absolutely none besides the Liberty Station which only sells 87 Ethanol Free. I know 100% this stuff is my problem so if I am going to go with Ethanol Free I am going to have to buy it somewhere else with a better rating. I am on the Panhandle of WV so I surround a lot of other states and the site wants you to search by state so it is a little counter productive for me. Maybe you could take a look at tell me exactly what I should be looking for?

Also about the MS 290. I am basically the "NAK" (Neighborhood Arborist Kid) and I am getting ready to invest in a MS 660 Magnum with a 28" Bar. I honestly can't wait!

 

[CR888]

Good post above and the only thing l could add as l am no fuel expert by any means is that l find all my gear prefers the standard E-free 91 unleaded. Fresh fuel is a must IMO. My saws don't run as well with the premiun high octane stuff. Also the turnover is a lot higher on standard 91 than premiun thus fresher fuel. We get good fuel here though. l too would forget 'race' fuels on stock saws. Engineers design OPE around standard 87-91 octane not race fuel or premium. Higher octane fuels probably need higher compression engines to take advantage of it. Understanding detonation enviels this.

 

[windthrown]

I get premium E0 gas because that is the only E0 gas that you can get in OR and WA now. My saws run better on it, and I ran premium gas in my saws before E10 came along anyway. I found that my saws all picked up revs after switching from dyno to full synthetic oil as well. Also note that there is 4% more energy in pure gas than E10 gas (ethanol has less energy than gasoline does).

Also: whatever you run, re-tune your saw carbs after switching between gas/oil types. It will make a difference.

 

[windthrown]

Using the Pure Gas web site, you certainly do live in the E0 higher octane desert. All the E0 anywhere near you is 87 octane. Not even mid grade E0 is anywhere close in PA, VA, MD or WV. That sux....

 

[jimrb]

Isn't midgrade fuel at many stations a blend of high test and low test? Point I am making is at my stations the premium fuel is really that stale, just might not be sold as much as the lowest grade. My car and truck are diesel so I can't buy midgrade to watch the pump counters spin at the pump. If you look closely you will see 2 or three counters. One for diesel and the other two for low and high test gas.

I happen to use high test (92 octane) for my lawn mowers and 2 cycle engines in hopes that it might be ethanol free. I can start my engines after they have sat for a few months. No signs of ethanol corrosion, which I guess is more water corrosion, yet.

 

[Hexa Fox]

Using the Pure Gas web site, you certainly do live in the E0 higher octane desert. All the E0 anywhere near you is 87 octane. Not even mid grade E0 is anywhere close in PA, VA, MD or WV. That sux....

So if I can ask what would you do if you were me? Because I sure can't afford a can of $10.00 MotoMix every time I go to work. Should I shoot for the Racing Fuel? It will stay good longer right even though it probably has Ethanol in it or rather something else?

 

[windthrown]

I would use premium E10 with stabilizer in it. I used it in my saws for a year here when that was all could get. Racing fuel will not do you any better and it is a lot more expensive. Just keep the gas dry and away from water, as ethanol likes to suck up water. Any slosh of water in the gas can and it is toast, even with stabilizer in it.

You could also do a blend of 87 E0 regular and 91 E10 super, and make your own low ethanol E5 89 mid grade. I do not know what your E10 gas really is. It may not be that bad. In California it was 6% last I was there. Here it is full 10% ethanol, the max allowed. Frikke'n Oregon used to be all pure gas until the greenies went wild. Washington held out for another year, and then they rolled to E6 and then full E10. Then the marine engines started blowing up left and right, and they screamed bloody murder. So the state passed an exemption allowing premium E0 gas, and it is sold at more places here now, but for a 15% premium. For plain gas...

 

[windthrown]

Isn't midgrade fuel at many stations a blend of high test and low test?

Here in the west mid grade comes from the refinery blended that way. We get all our gas from Washington state in Oregon, as there are no refineries here. Lots of super and turbo charged auto engines require premium now, so it sells more than it used to. As for gas getting older in the station tanks, it is fresher at stations that do more business. For that reason I get my E0 gas at a busy station that gets 2 trucks of gas a week. I avoid mom and pop places out in the boonies that do not get as many deliveries. Also US gas is rated as an average of refinery fresh and pumped into your car. So it is already dropped in octane by the time you pump it, regardless.

 

[mdavlee]

I use 87 in modded saws with no ill effects. If you have e free 87 use it instead.

 

[Hexa Fox]

I use 87 in modded saws with no ill effects. If you have e free 87 use it instead.

We just got done talking about that. The only ethanol free stuff over here comes from a station called Liberty Station and it is 87 but my chainsaw won't run on it on account of how badly degraded it is. Then as windthrown just pointed out I have no place near me that even sells half decent ethanol free. This is probably why my nearest certified Stihl Mechanic told me to find the highest grade, freshest stuff possible and go with that. As we really do not have a choice. Either that or MotoMix. Which is why I am considering just going out and buying the Racing Fuel. Even if it helps a little bit it will be worth it. Especially if it is fresh and can sit for a little while.

This is probably my main problem though because as windthrown pointed out the ethanol can absorb moisture over time. Another reason my Stihl Mechanic told me to dump it out after every three months at a minimum. My neighbors around here buy nothing but Stihl and they use gas mix that is years old and have absolutely no trouble. People told me nothing good can come out of using fuel that bad but so far I haven't heard any of them say they are having trouble with their saw. I am was the only one and it was when I used that crappy 87 ethanol free stuff.

As soon as I put that garbage in my saw and start it and it works whatever other gas it had in it before out and starts on the ethanol free stuff it immediately dies. I'm also talking fresh stuff that I just got from the pump hours before putting it in my saw. Then it will not start at all after that. I honestly no lie think I could put beer in it and it would run longer and better.

 

[Hexa Fox]

Long story short that garbage will kill my saw long before the moisture in the ethanol does. From the way things look I do not have a choice but to try to find fresh premium grade fuel either.

 

[Hexa Fox]

I wish MotoMix was affordable but for some of the operations I might be taking in this year it certainly is not. Especially when I pick up my MS 660.

 

[mdavlee]

Have you tried to retune it for that fuel? If you get racing fuel you're going to be way rich and will need to retune to get it to run right. VP gas in 5 gallon pails would be your best bet. It will last a year in a cool place.

 

[Hexa Fox]

Have you tried to retune it for that fuel? If you get racing fuel you're going to be way rich and will need to retune to get it to run right. VP gas in 5 gallon pails would be your best bet. It will last a year in a cool place.

Sadly I do not know the first thing about tuning a chainsaw. Is it tough? How would I know how to tune it for a specific fuel?

 

[Hexa Fox]

Have you tried to retune it for that fuel? If you get racing fuel you're going to be way rich and will need to retune to get it to run right. VP gas in 5 gallon pails would be your best bet. It will last a year in a cool place.

I just did some research after I read what you wrote again and came across this.
http://www.vp-sef.com/index.php/products/pro-max

Good advice mdavlee. I looked up a dealer and there is one close enough. I might have just found my alternative. However would I still need to tune my saw or make adjustments for it to run on that stuff there in the link?

 

[mdavlee]

I just did some research after I read what you wrote again and came across this.
http://www.vp-sef.com/index.php/products/pro-max

Good advice mdavlee. I looked up a dealer and there is one close enough. I might have just found my alternative. However would I still need to tune my saw or make adjustments for it to run on that stuff there in the link?

Madsens has a good link for carb tuning or you could pick up a tach and use it. More than likely the saws will be a little rich on that fuel.

 

[groundup]

I too am in the "e free desert"

I have an airport close by and run av gas. I have been running it for awhile mixed 45 to 1 with Stihl synthetic. I am running my 660 on stock settings and its running a little rich which is fine with me. The other saws I have been running on it are self tuning so no issue there.

I contacted Stihl regarding running it, they said don't run it because of the high octane. I use ethanol 92 octane when milling but buy it one day and use it up the same day

I find the saws run cooler using av gas.

 

[groundup]

Madsens has a good link for carb tuning or you could pick up a tach and use it. More than likely the saws will be a little rich on that fuel

You really should get a tach and/or learn to tune by ear. You'll burn a poorly tuned saw up quicker than one running ethanol gas.