I don't envision a computer controlled injected 2 stroke chain saw in the near future - the extra weight and the durability concerns make it somewhat unlikely in my lifetime for any but the largest professional saws. The day of the gasoline consumer saw is likely coming close to an end with new electric saw technology advancing very quickly.
The manual with my saw recommends a minimum of 89 octane... I use ethanol free premium gas along with synthetic 2 cycle oil (STIHL HP Ultra) that has fuel stabilizers. In the past year or so one of the chain convenience stores started carrying ethanol free premium gas and they are adding store locations steadily over time--I've got one 7/10ths of a mile from my house now. I started using this mix in all my Stihl 2 stroke equipment (string trimmer, hedge clipper, chainsaw), and the gas in my mower, and everything runs better.
I would expect your saw to run cooler, and better, with the premium fuel as compared to say 87 octane based on my saw's manual:
"Use mid-grade unleaded gasoline with a minimum octane rating of 89 and no more than 10% ethanol content." "Fuel with a lower octane rating may increase engine temperatures. This, in turn, increases the risk of piston seizure and damage to the engine."
John
The higher end Stihl and Husqvarna professional saws have engine management systems available that electronically control the ignition timing and fuel metering... Both claim to compensate for different fuels, altitude, humidity, temperature and clogged air filters.
Stihl's is called M-Tronic and Husqvarna's is called Autotune.
That said, the average homeowner or farmer probably isn't going to buy one of those professional saws... they are costly and excessively powerful for what mere mortals need in a chainsaw. The guys making a living in the woods or doing serious tree work are more likely to spend the big bucks...
John
Found some videos:
Stihl's video...
Husqvarna video...
I run nothing but ethanol free premium gas in ALL of my small engine equipment. For the small amount of fuel I put through them in a year, the difference in cost is a non-issue, particularly considering the possible costs of the alternatives. A screwed up carb or a scuffed piston or siezed engine is too costly to consider trying to save the
7 cents a liter or whatever.snipped-for-privacy@snyder.on.ca wrote in news:h6318btmbetdivcklbp6av5kmi157ut0rd@
4ax.com:
You are confusing two different things here, both of which ethanol happens to be good for.
One is octane rating. Raw gas (no additives) has an octane rating (*) of around 70, so something has to be added to raise it to a useful level. Historically that was tetra ethyl lead, which of course is now banned. Ethanol has an octane rating of around 110. So adding ethanol to gas is a very effective way to raise the octane rating.
The second is oxygenation. In ideal conditions there is enough oxygen in the air entering the engine to completely burn the fuel. Ideal conditions don't always occur, so a fuel additive that contains oxygen can help get to complete combustion. Ethanol contains oxygen, so it is effective as an oxygenator.
Until 2007 there was a Federal requirement (in the US) to include oxygenators in fuel. That requirement no longer exists. The reason ethanol is added to gasoline now is for it's value as an octane booster.
(* octane rating is a confusing thing, because there are several common ways of testing it, which give different numbers. In North America the AKI (or R+M/2) method is used, which is what the numbers above are based on).
John
"John Grossbohlin" wrote in news: snipped-for-privacy@earthlink.com:
Don't forget the tool junkies. "This thing has electric start, SparkAdvance(TM) (tm)* that automatically fires the spark before cylinder reaches TDC, TriggerValves (tm) that restrict fuel flow when you're not running full speed, and OxoInject (tm) for mixing fresh air with the fuel for better burn!"
Puckdropper
Leon wrote in news:OfKdneLr snipped-for-privacy@giganews.com:
Typically differences in detergents are between brands, not between fuel grades. The vendors would like you to think there's extra "good stuff" in premium (especially now that it costs $0.50 or more above regular), but other than octane boosters it's generally not so.
I am also dubious that premium would be alcohol-free. I suspect if it was, it would be prominently advertised, and I haven't seen that anywhere.
John
Different strokes for different folk, John.
Saw Shell advertising ethanol free premium up in Wisconsin. Not so here in Illinois (at least not in the NE corner of the state - down south it's available in some areas).
I think, but not sure, that Shell's ethanol free was tied in to their "V-Power" blend or somesuch
Actually Shell advertizes Nitrogen, V-power Nitro+ Premium, for better cleaning only in the Premium.
But typically most all better brand fuels have similar additives in all grades.
Well if it was advertized alcohol free they would certainly catch a bunch of flack from the tree huggers.
Down here their pumps only claim "May" have up to 10% alcohol.
That is the way it is in Texas/Houston
A shot of ether and the sucker starts like a champ.
I've had the same chain saw since around 1978. The first tree I cut up it blew up. My neighbor, a farmer the first 20 years of life, owned a two man auto repair shop the next 50 years, and a lawnmower repair shop the next 25 years, told me my mistake was using the 50-1 chainsaw oil mixture recommend by Sears. He said use regular 20w non-detergent in something like 9-1 or 20-1, can't recall, it's written on my gas can in the shed. He said it might smoke a bit, and be hard to start but it will never freeze up. Arguing with a 95 year old dude that still worked on small engines 9-9 6 days a week seemed silly, so I gave it a shot.
It was always hard to start, so didn't notice a difference, but learned to use ether to get er running (even though I was often told ether would hurt the engine)
I rebuilt the engine, took his advice, and now, almost 40 years later, the saw still runs great. I haven't used it much lately, getting old, but last I used it it still ran, and smoked like a champ...
Also, as far as premium gas in a chainsaw, my guess is once you dump oil in the gas, it doesn't matter much.
Hydrocracked/catalytic cracked first run gasoline has an octane of up to 90 with no additives.
There is no such thing as an "octane" rating of over 100. Over 100 it is an "aki" or antiknock index..
Then why is ethanol added to regular gas at 10% and not added to premium (in very many cases)???
The ethanol is added to regular gas because that is the easiest way to sell the volume of ethanol mandated. The total amount of gasoline sold in an area needs to contain, say, 9% ethanol (maximum limit is 10%) and 99% of gas sold is regular (or a mix containing regular) so they do not HAVE to put it in the premium gas.
Also, the ethanol is not added at the refinery (at least in many cases) it is added to the tanker at the depot - so the regular gas at the depot has to be 97 octane without ethanol.
I don't "buy" the ethanol as octane booster arguement - at least here in Ontario. Does it increase Octane? Sure. Is octane the reason it is added? No. It is added because it is mandated. It is mandated because it is an oxygenator. The octane boost is just a bonus. (which helps mitigate thedilution of the fuel energy caused by the dilution of the fuel with low energy ethanol in the eye of those who don't understand octane requirements and energy content and the fact they are not connected in any way)
Might be true in the USA, but the total additive package in tier 3 premium gas is significantly different than in the same brand's regular gasoline
Shell Canada has gone on record saying there WILL BE no ethanol in their premium gasoline.
If you look at PurGas.org? the vast majority of stations selling ethanol free gasoline sell only premium ethanol free gasoline. The only major resellers of ethanol free regular are marinas.
Mogas for aircraft use is also ethsanol free premium. No Mogas STC allows ethanol fuel.
Doesn't need ether - it USUALLY starts on the first or second pull. But if it decides to balk instead, it snaps back with fury!!!!. I won't start it on a ladder or in a tree. Too dangerous if it "gets angry"
I tend to use 40:1 instead of 50:1 so it does smoke - but it is close to 50 years old and has never been apart. And other than the extreme high compression kickback, it is NOT hard to start. I run ethanol free premium, and even after sitting for 2 years with a full (sealed) tank, it started on the second pull.
If 93 octane drops to 87, think where 87 goes!!!! The more oil, the lower the octane - one advantage of the lighter mixes.
Using higher octane than required won't hurt anything except your wallet.
I remember when "Leaded Regular" was 91 octane.
I do the same. I have a 4 cycle mini-rototiller with a Honda mini engine. It has been a problem from new, had it serviced and not much better. It was hard to start and would stall after running a few minutes, and then only run a minute or so after starting hot. This was with regular 87 gas. I also have a Honda weed wacker with a mini 4 stroke engine that runs fine with regular
87 fuel.Switched all my small engines to Shell premium, they run great and even the difficult mini-rototiller Honda now runs properly with only a change of fuel to premium.
The added cost of premium is insignificant compared to frequent servicing required when they don't run properly. By the way, I have a Honda self-propelled walk behind mower that is now over 25 years old and has never needed service other than oil changes. It starts on the first pull.
And i remember having to settle for something like 71 octane because it was all I could get - at $1.65 a liter - back in '74 in Livingstone Zambia. The old '49 beetle didn't care, but the 204 Peugeot wasn't happy untill I cranked the timing back. You could drive the stage 3 Mini Moke into the shop with the key turned off after you got it warm........
Those things are sensitive, and with no carb adjustment available they run just enough too lean on Hooch that they hardly run at all..
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