the lead could foul the plug, seen it happen on lawn mowers
framtech,
Oct 19, 8:38pm
Funny thing is lower octane fuel has a higher calorific value (produces more energy per unit) it's more about the speed of the burn. Ive been using 91 in my chainsaws for 40 years, in fact I have a small echo trim saw that is a least 40 years old now and still going strong( it must be on its 20th bar and 40th chain). Whats changed over the years is the pump gas is lead free (except for avgas which I understand still has shitloads of poisonous tetraethyl lead in it). All this bullshit about fuel, in a now throw away society is a bit of a joke. I could understand when they stopped using lead in fuel and valve wear but if you run the average shopping basket - i wouldn't lose any sleep over the fuel - use what gets you the best economy (by real testing not keyboard warrior estimates), The computers in modern cars will tune to be safe (knock the spark back but be less economical), your pocket is the test.
framtech,
Oct 19, 8:46pm
Avgas is an issue in gear that uses O2 sensors and should really only used for airplanes and race motors that have high compression ratios.
marte,
Oct 19, 8:52pm
Higher octane fuel is for higher compression motors that will cram more air & oxygen into the compression zone for a better explosion, without preignition ( Well actually it's a 'rapid expansion of gases' as Intrade mentions, it's a 'Slap', not a bang )
How a engine compensates for lower octane & preignition, is to inject more fuel to dampen out the air/fuel mix, which just means it uses more, of a cheaper fuel. While the extra petrol has a tendency to wipe more lubrication off the cylinder walls & away from the rings. Which causes lots of problems in European cars.
Handy if you have a Japanese car. It's printed on the inside of the fuel cap, even if it's a ex Japanese Euro.
Regular gasoline (レギュラー), 89 Octane or above High-octane gasoline（ハイオク）96 Octane or above, but normally 98+ Diesel（軽油）
mrcat1,
Oct 20, 12:07am
Lead in petrol will give the exhaust a nice grey look if its running properly. Lead in petrol isn't new, was around for years and years before they stopped it.
mrcat1,
Oct 20, 12:09am
And catalytic converters, could block them up.
ambo11,
Oct 20, 8:08am
95 fuel and top quality synthetic 2 stroke oil. I run Mobil 2 stroke racing in all my saws, burns clean with no smell. Also clean the air filter properly and often, and keep your chains sharp. Saws will last forever.
drog,
Oct 20, 8:42am
This. This. This.
lythande1,
Oct 20, 8:46am
[quote=gpg58I too would never use 91 in anything, especially a chainsaw, unless you want hard to start and gutless. [/quote] Haha. We've had the chainsaw for years and years, it's still not hard to start nor gutless.
gpg58,
Oct 20, 8:59am
Haha. We've had the chainsaw for years and years, it's still not hard to start nor gutless.[/quote]
But have you actually tried higher octane, and compared cutting performance? I have, and know how much better both of "Mine" go, with the good stuff, and start second pull on first use each day. Have also compared lawn mowers in long grass, so much more grunt. Also every motor vehicle "I have tried", gets more kilometers per dollar, on 95 versus 91.
nice_lady,
Oct 20, 4:45pm
It's be surprised if the weed eater had anything but a very basic two stroke?
Probably wouldn't bother with the avgas even tho it's free maybe just 95 might be a sweeter run for it?
desmodave,
Oct 20, 5:17pm
I too would never use 91 in anything, especially a chainsaw, unless you want hard to start and gutless. Personally my stihl 192t prefers 100 race gas So what story do ya want to run with ? . I see a paradox . Any tuning with these fuel changes . Avgas eh , all that power in a top handle . Be careful .with it . I have a 192t and 3 other top handle saw's . I cant say i have noticed any sudden seat of the pants power increase between fuels , but a sharp chain works for me .
Free , is some1else paying like ? or is old stock going out the back door .
desmodave,
Oct 20, 5:37pm
Good opportunity to film your timed cuts gpg58 , load them on youtube run against the watch . Really interested in seeing a avgas run .
marte,
Oct 20, 5:48pm
I googled it. First at the top of the page. Quote {To start, both Stihl and Husqvarna recommend the use of high octane unleaded gasoline. Both brands of pro saws are designed to burn fuel rated at 89 octane or higher. Most regular grade fuel has an octane rating of about 87. This is not enough. We also don't recommend the use of high octane aviation grade fuel.} This is a American site, so their octane ratings lower than ours & so our 96+ would be appropriate. They also explain a lot of other stuff properly.
Interesting, as a 2 stroke has a shorter power producing part of its stroke ( power band ?, LoL ) because as soon as the exhaust ports open, it's not getting any more 'push' any more, unlike a 4 stroke that will get it right to the end of the stroke, but 1/2 as often. So on a 2 stroke you want a fuel that's going to burn its energy really quickly, before the exhaust ports open. Not after as then some of the expansion energy's going right out the exhaust, so the correct fuel will make a dramatic change in exhaust sound compared to the wrong fuel.
The exhaust ports don't open like a 4 stroke engine, as the piston goes back down the cylinder the exhaust port is in the side of the barrel, so effectively the piston is the exhaust port valve.
jacinda2059,
Oct 20, 7:21pm
I ran 6 huskys, for many years on 95 petrol, and used 40/1 castrol super two stroke oil. had no problems.
marte,
Oct 20, 10:04pm
Yep, that's what I mean, the ' rapid expansion' of gases would have to be a shorter duration in a two stroke or it would blow a lot of energy out thru the exhaust port. Ok, a 4 stroke would gain extra power from that last bit of expansion, but what might work in a 4 stroke, wouldn't in a 2 stroke. I guess we start moving into a 'bore X stroke' conversation here.
Something I was taught with chainsaws, and I do it with angle grinder because it's the same theory. Is to open the throttle & wait till it's up to top revs before applying the tool to the job. ( The grinder 'rings out' ) That way it's momentum has built up & it's at max effiency & can cut better.
Too often I see chainsaw operators rev it up & push it to the job, start cutting, then open the throttle up & you can hear the chainsaw bog down. I used to do that with the grinder untill I learnt & then changed how I did it & it works much better now.
nice_lady,
Oct 20, 11:24pm
Hubby works at an airport. The fuel is perfectly legitimately collected and is indeed free.
desmodave,
Oct 21, 6:57am
Yes he is a tanker driver , x Valiant owner and says a lot :-) Good score , but some where some1 is paying . Is it the remains of part drums and tanks perhaps . Burn it while they make it .
desmodave,
Oct 21, 7:37am
Glad you got something out of that link . I like the slap and punch explanation . So many little domestic type saw's get sold with longer bars than ideal so have to work overtime from day 1 .
nice_lady,
Nov 4, 8:46am
Drains
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