2 cycle engines - Sthil product= keeping running ?

I have been using a product recommended by the local Stihl dealer, it's called Opti 2 two stroke mix, one pack in with one gallon of gas,and use it in everything no matter what the ratio is supposed to be. It also has a built in fuel preservers. I love it,one gas can for everything. Been using it 2 or 3 years now, haven't had any issues.There is a noticable difference in how they start and run,way better. I use Opti 4 in my zero turn with a Kawasaki engine,if I ran that from the day it was new Opti 4 gives you a 7 year warranty on any engine failure.

I have a 021 (I think) chainsaw that I couldn't keep running. Got to digging around trying to find out why and found my fuel line had a small crack. Put a new fuel line and filter on it and haven't had any problems for a couple of years now. I use regular fuel and Stihl 2 cycle oil mixed at 50:1

when i was cutting more than i am right now, I also mixed my own gas/oil, used oil that was branded with the saws i have. (echo) have never had a problem that way. after using one saw more than the others, the others have the same problem as you are experiencing. i then take them to a small engine dude locally and he goes thru the carb, then they run excellent again. sometimes the seals dry out and sometimes the carbs gum up. I use 87 at the pump. alot of times the gas will evaporate and leave to much oil.

I have a Stihl 250 that is about 10 years old... It started the sputter , no high speed, chit.. a couple years ago... Cleaned the carb and it would work for a couple hours..

I use Wal-mart's brand(Crown) camp stove fuel.  Its Naptha, same as old mobil white gas. Last time I bought a gallon of it, it was $13+/- .  So it ain't cheap, but its cheaper than a new carb...

My friend had a brand new Still that wouldn't keep running. Started well and ran well then would quit after a bit of work. He had it to dealer twice. No problem found. He brought it to me. I started it and went to woodpile - I always have a pile of wood to cut. Worked it hard for maybe 15 min. Stopped in its tracks and would not restart.  Saw was very hot. I took it in shop and let it cool. Asked him how he mixed fuel - he said 50:1 as per manual and dealer instruction. I said we are going to do a little experiment. Dumped his fuel and filled with my 24:1 mix that I use in all my old Pioneer saws. Took it out and cut till it ran out of fuel. Was still cool. He took saw home and no more issues. Just mixes a bit richer. 

Edited by Ed (Ont) - 07 Aug 2022 at 8:36pm

Also check the spark arrestor on the muffler. My Stihl weed eater gets the arrester cleaned every year now. Use pure 91 octane gas with to 50-1 stihl synthetic mix.

I have an old Homelite chainsaw that I bought in 1977. Use regular gas with e10 in it. When I use it I just use a 16.9 oz plastic soda bottle and put in half an ounce of 2-stroke oil oil. Should be 32-1 ratio. After use I drain it and then start and run all out of the lines. Knock on wood has worked good for me.

My Stihl dealer says he would rather use 87 octane ethanol free than 91 octane w/ 10% ethanol, and he can get that 87 at his local gas station, so that's what he recommends. His reasoning is Stihl has a little bit of a safety factor built in their octane recommendation, and if you know you're getting fresh, good quality 87 octane then you should be fine, since to him it's more important to not run ethanol. He's been in business for a long time.

To the OP there is something wrong with your saw and trimmer

Just ran one of my old saws tonight. I use regular gas #87 from pump and mix with snowmobile oil that I always have on hand. Hadn't been drained. Filled with fuel left over from last fall. I keep meaning to drain it but sometimes never get to it. Worked great. Not sure why others have so many issues. I do store all my saws in shop that is fairly constant in temperature so I think that helps. 

Edited by Ed (Ont) - 09 Aug 2022 at 8:01pm

Amos wrote: To the OP there is something wrong with your saw and trimmer I use premium non ethanol fuel 93 octane Klotz oil 44:1  a normal day is about 2 1/2 gallons though my saw(s)  I fell with one buck with one and there's a spare ride the skidder.  Never do they not start on the second pull cold or first hot.  Fresh fuel is the key and keep them clean fuel and air ...don't run them dull

Not much difference between old and new saws. Still carbureted and 2 stroke. Only difference is new ones are running leaner - to a point. As I said in my first post the new one did not work on the lean mix either. Worked great on my 24:1 mix which is what I use in all my old pioneer saws. The old ones need a correct mix too or will fail. I may try a bit leaner mix in the old ones. Maybe 30:1. I have used lots of new saws. I prefer my old ones.

Edited by Ed (Ont) - 12 Aug 2022 at 7:13am

I buy the 40/1 true fuel it's expensive use it in the first and last tank of seasonal equipment. The weed whackers thstget used all summer just mix 87 and oil. At the end of summer use a tank of premixed empty and run out.next spring fill with premixed for the first tank
My oldest are from the 1980s

What would be a reasonable mix, when using motor oil, with 87 octane?