Chain saw gas choice

[dnastrau]

Greetings:

I have read so much on the 'net about what fuel and oil to use in chain saws these days that my head is spinning.

I have a couple of Poulan light duty saws as well as a Makita DCS6401 (made by Dolmar in Germany) 20" heavy duty saw. All of them call for 87 octane (87 octane R+M/2 method in the US and Canada, 91 research octane elsewhere) based on the owner's manuals.

I am going to start using synthetic 2 cycle oil due to the apparent benefits. However, my main concern has to do with octane and Ethanol. I have read a lot of recommendations that 87 regular really isn't the best fuel for chain saws and that you are better off using 89-93 instead. Some say this has to do with the amount of Ethanol in fuel these days, but here in northeastern Pennsylvania, nearly all fuel has 10% Ethanol in it - regardless of the octane.

What are the opinions on using mid grade or premium fuel in chain saws? Is there really any benefit?

Thanks in advance!

Andrew S.

 

[SuperDave456]

I use 93 octane in all my lawn equipment.
However a 2 gallon can of gas will last me 2-3 months. It seems that even with a fuel stabilizer that the fuel begins to break down and it has been my experience that higher octane fuels run better after a longer term of storage than compared to lower octane fuels.

If you are going through a gallon of gas pretty fast I would just stick to 87 octane with a decent 2 cycle oil with fuel stabilizer.
If you plan on keeping your saw and can stored for awhile I would stock up on higher octane stuff.

 

[IndyIan]

I don't think there is a downside to higher octane gas. I think of it as bit of extra protection in case the saws aren't in perfect conditions... Say a small airleak bringing up the cylinder temperature to where 87 will start to ping.
Also if you keep your gas for a while it has a far better chance of being atleast 87 octane if it starts at 91!
Also 2 stroke oil kills octane rating so if you run a bit more oil that 50:1 its not a bad idea to up a grade in fuel.

 

[bullwinkle]

I always run premium in my Stihls (chainsaw & brush cutter)-it helps with starting & they seem to have more power-one word of caution-now that it is impossible to get ethanol-free gas-always drain & run your 2-stroke fueled equipment dry & don't keep 2-stroke gas for long. The ethanol in the fuel will absorb moisture from the air-which could cause engine damage (the water can't carry the 2-stroke oil along with it)!

 

[SuperDave456]

Something I have always been curious about.

What do the fire fighters up and down the West Coast use?
Is it any different than what loggers use?

Being from central Texas the only large chainsaws I see are at Lawn stores. They are more of a display item than for actual use, 4-6' bars are WAY to much overkill for the smaller trees we have around here.

 

[tom slick]

The local USFS uses a lot of Stihl MS250 with 18" bars. I'm sure there is at least one guy on the crew with a 36" bar.

 

[hemitom]

I have used mostly 87 gas in my saws and trimmers, i tried sunoco 94, esso 91 and never noticed any difference between regular and high test. My advice to you would be the money you save on using regular gas put into a good syn oil. this is the only difference i have ever noticed in my equipment. Less smoke, idle is some what improved seems to have a snappier throttle response and burns much cleaner.

 

[boraticus]

There's no advantage to running higher octane fuel in a two cycle engine unless it's been highly modified to increase compression substantially.

I run nothing but regular pump gas in my two Jonsereds and one Echo chainsaws. Never a problem. The Jonsereds saws are considered among the best saws made and the models I own are high performance units. The Echo 346 is also a professional grade saw.

All of my 17 or more two cycle machines get regular pump gas. Even my modified vintage Yamaha two stroke motorcycles.

 

[IndyIan]

Which jonsereds do you have? My husky 372 says use atleast 89 octane in the manual. I guess if its working for you, who am I to argue that you should get anything else but I'll stick with 91 octane. Fuel costs are not really a factor for my small engines.

 

[engineerscott]

If you can find ethanol free gasoline I'd use that, regardless of octane rating. Alcohol in the fuel is a much bigger issue than whether you are using "Premium" or "Regular".

 

[dnastrau]

Ethanol-free gas is nearly extinct around here - every station that I have gone to recently only has E10 now. It is my understanding that it will be mandated that all gas have at least 10% Ethanol eventually.

I bought some synthetic 2 cycle oil last night and will probably use 89 octane. My hope is that the synthetic oil will help to protect my engines better than the dino 2 cycle oil. Since the pumps say "up to" 10% Ethanol for all grades, I guess the octane question becomes less important since they all have it.

 

[boraticus]

Originally Posted By: IndyIan
Which jonsereds do you have? My husky 372 says use atleast 89 octane in the manual. I guess if its working for you, who am I to argue that you should get anything else but I'll stick with 91 octane. Fuel costs are not really a factor for my small engines.


I own a 1984 Jonsereds 630 (61 ccs) and a 1986 670 (67 ccs). Both large high performance saws. As you can see that these saws are around 25 years old but still running like the day I bought them and they've seen plenty of hard work.

Some documentation for European products specifies an octane rating of 90, based on the RON standards used in Europe. This is the equivalent of an 87 rating under the Canadian AKI standards, which is similar to USA standards.

Possibly the reason for the higher octane recommendation in the manual is due to European fuel octane rating standards.

 

[mrsilv04]

The best thing that you can do is to mix it in small batches and to simply keep the fuel FRESH.

If it has sat for a while, dump it in the car and go get some fresh fuel. Buy from a gas station that sells lots of gas.

That's the easiest thing you can do to keep 2 cycle engines running well.

I also buy my gas for my small engines from a "Top Tier" retailer. However, fresh fuel is much more important than anything.

 

[JTK]

Originally Posted By: mrsilv04
The best thing that you can do is to mix it in small batches and to simply keep the fuel FRESH.

If it has sat for a while, dump it in the car and go get some fresh fuel.


That's exactly what I do. I've got 3 five gallon plastic cans I store gasoline in, and a dinky 1 gallon can for premix. What I don't use over a period of time gets dumped into the riding mowers.

Joel

 

[IndyIan]

Well the manual says 90 RON is the minimum allowable octane but use higher octane if you are using high revs like for limbing. Also it says to use husky 2 stroke oil at 50:1 and other oils at 33:1. I don't run XP oil so I just mix my gas at mid 30's to 1 which lowers octane some more.
I'm about to tackle a pair of 3-4 cord(each) ash trees so my saw is going to have its bar buried for a minute+ at a time. I think it will be prudent to run 91 octane. Its going to be a bit tougher than buzzing through 20" rounds that I normally do....

 

[boraticus]

Black ash or white ash?

Either way, that sounds like some huge trees. Takes a fairly sizable tree just to make one cord.

 

[steve20]

you will love the syn oil in 2 cycles- I have a supply of Mobil-1 2T from when it was available---virtually no smoke or oil related fumes to deal with

OP: you may want to try a Valero station-I heard they were one of the last holdouts on E10


steve

 

[Johnny]

Originally Posted By: SuperDave456
Something I have always been curious about.

What do the fire fighters up and down the West Coast use?
Is it any different than what loggers use?

Being from central Texas the only large chainsaws I see are at Lawn stores. They are more of a display item than for actual use, 4-6' bars are WAY to much overkill for the smaller trees we have around here.


Back in the day I cut many, many cords of oak in central/east Texas (Fairfield/Buffalo area) with both Stihl and Husky saws using a 24" bar.

I know a lot of loggers here in WI and the Stihl and Husky saws they use are the same ones the average consumer can buy at the local Stihl or Husky dealer.

 

[IndyIan]

Originally Posted By: boraticus
Black ash or white ash?

Either way, that sounds like some huge trees. Takes a fairly sizable tree just to make one cord.

I don't know which they are, the roots aren't wet wet, but they've had no lack of water either...
This one is about 45" at the butt and stays that way up to 16' so that 2 cords already. They are on a field edge so they branch out after that but some branches were over 20" in diameter.

Suzie is in the corner, she's a 105lb pup for scale.

 

[Johnny]

Now that's a tree.