Something to consider is that we are running 2 stroke engines. And these burn a mixture of gasoline...
and
OIL-
What is the octane rating of oil? There isn't one, because it is very LOW. A small amount of oil DESTROYS your effective octane rating instantly. Which means that even if you use 100LL blue avgas like one guy on this thread talked about [How? It is illegal to dispense that into cans]...your final octane rating is going to be real low, probably below 80. That is why two-stroke engines typically run very low 5-6:1 compression.
However, I've been told that many car racers use a certain grade of Valvoline 2 stroke oil in their dry sump racing V8's because it actually has some sort of octane enhancer. I cannot remember which Valvoline it is, but Mark Anderson from California used it in his Porsche 928 race car when he took it to the Silver State challenge in Nevada. This is where they close a 100 mile section of highway in the middle of nowhere and people race their cars on it, trying to come as close as possible to a defined time. Mark's 928 has a 396 cubic inch four cam/32 valve Porsche V8 that with catalytic converters installed can PASS California emissions. In the race, at one point his car was clocked at 211 mph, and it won the 200 mph class. It used this Valvoline 2 stroke oil in the sump, and after he won the race, he put the trophy in the hatch, changed the tires to street tires...and drove it home! Find this oil for your saw.
The thing to WATCH OUT FOR is ethanol!
Ethanol is drinkable alcohol. And it is typically about 10% of the fluid you buy at the pump. By volume it has about 60% of the energy of gasoline, so if 10% of your tank is ethanol, you lose about 4% energy for the same price. This is a scam perpetuated by the corn lobby, but I will stop right there. Ethanol attracts water from the air LIKE CRAZY! The entrained water then goes to work on all your metals, exchanging its oxygen with the metal to produce rust. In areas that you DO NOT want rust! Right now, lawnmower and small engine repair shops are doing gangbusters business repairing these devices simply due to the damage that this silly politically-demanded ingredient in fuel is causing.
For that reason I purchase nothing but ethanol-free fuel called REC-90 for my boat and all my small engines. You can find a station that sells REC-90 here:
Ethanol-free gas stations in the U.S. and Canada