I bought a new, little, chain saw last year. It's a Stihl MS 170. Last year I used it for doing some trimming last year and mixed up the gas with the oil that came with the saw. Last night we had a storm and a few limbs came down. I need to mix up some more gas and I have a bunch of different two cycle oil. I was reading the manual, for the saw, this morning. It says in the book to NOT USE two cycle oil that is rated for water cooled, or both water and air cooled two cycle engines. It says to use only oil rated for an air cooed engine. I guess I had never heard of this before. I never paid any attention to what the two cycle oil was rated for. When I was younger and heated with wood, and ran a chain saw a lot, I never paid any attention to what the oil was rated and never seemed to have any trouble.

I have a bunch of two cycle oil but it is rated for both water and air cooled engines. Anyway, is this something new. Should I really be concerned about, using oil rated for ONLY an air cooled engine.

Well a water cooled engine is a much more efficient cooling system. . Oil is definitely not created equal. I wont buy off brand oil. Like caseys oil. who knows whats in the jug? I like stihl products. I just buy the little orange bottles of oil that stihl sells. No clue who the oil actually distilled and bottled by but no problems with it. I like that each little bottle is the correct amount for one gallon of gas. I buy gas without ethanol for all my boat motors, chainsaw, lawnmower etc. Costs a little more but fuel lines dont get eat up. I use that silver steak oil or whatever its called for outboards.

The book for this saw also says this saw is designed to run on gas mixed with ethanol. The books says no more than 10 percent ethanol. It also says make sure the gas you buy always the same percentage of ethanol as different percentages of ethanol can make the saw run at different speeds.

Run nonethanol fuel with Stihl premium oil and you are all set. Stihl has a 1 year extension of warranty if you buy/use the premium oil.

yepper is all i run in weed whacker and chain saw is in the gray bottles

and i run the pure gas too

It reads "no more than 10%", not that non-ethanol can't be used. Everyone would be better off using non-ethanol gas and name brand 2 cycle oil. Husky, Echo, Stihl, etc.

X2

That's correct. In reality I plan on using non-ethanol gas. It's easy to get just a mile down the road from my houses.
But, my question was about the oil. I still wonder what the difference between air cooled and water cooled engine oils is.

As soon as the store opens at 8 I'm going to go buy some Stihl oil.

I agree to stick with quality oil. I never heard of the water cooled stuff either, but in a two stroke engine it is the gas that cools the cylinder.

The problem with ethanol is the damage to the carb and fuel lines during storage.

Pete

Non ox and sthil oil

I've learned over the years with many 2 stroke engines the following -

Get ethanol free gasoline. Small engines don't like ethanol.

For best results , use the correct OEM oil for each different engine you have. I have used Mercury oil in a Evinrude engine and OMC oil in a Mercury product. There is a noticeable difference in performance. Each engine is specifically tuned to an exact fuel/oil ratio using that manufacturer's choice of oil blend.

Oil/fuel mixture is VERY important. If an engine calls for say 50 to 1 mix and you kinda eyeball it and end up with 45 to 1 instead , performance will suffer. Using the little bottles of oil to mix with gas is fairly accurate. However buying oil in bulk like gallon size you have to measure your own which can cause problems if not done accurately.

Many years ago I was in a chainsaw/lawn equipment shop getting a new chain for my saw. They had this funny looking plastic graduated cylinder cup on the counter. I asked the guy what it was for. He replied it was an ' idiot cup ' . He then explained that he would see time and time again engines coming into the shop for repairs because they didn't run right or not run at all. The ' idiots ' that owned them just mixed oil and gas haphazardly. He then told me how much better an engine set for 50/1 would run much better, start up easier, have more power at exactly 50/1 than even just slightly off at 51/1 or 49/1.

I bought one of those ' idiot cups ' on the spot for $3. I measure my oil as accurately as possible. Works great. Well worth the $3.

As far as air cooled vs water cooled oil requirements, the two engines run and act very differently to each other kinda like apples and oranges.
Found this online that describes it better than I could , short read but worth the info gained.
https://stores.dhsequipmentparts.com/blog/2cycle-engine-oil-vs-outboard-engine-oil/

If you are using a gas powered saw rarely. I recommend running Stihl Motomix. It’s good to sit for two years, no ethanol, mixed correctly, Packaged in a nice can. My two cents.

I have used the same 2 cycle oil in everything for close to50 years and never had a problem. I even intentionally mix my snowmachine fuel a little rich to provide better lube at cold temps

Working on the RR,we used a myriad of small machines.
Often when there was no mixing oil 10-w 30 was used in a pinch.
These small machines took a real beating on the RR,especially the chainsaws.
They always ran great and they were ran long and hard by lots of different workers.
Small machines and engines are a lot tougher than people think.
The worst thing for small machines is to let them sit for long periods of time.
If they are used all the time they run great.
I go out and start and run all my seasonal machines once a month all year long.

I do the same thing !

if you use less than a gallon of gas a year in that little saw the shelf stable canned premixed fuel is the way to go.

stihl, husky , true fuel , VP they all make it , when you buy a new saw they will double the warrant if you buy 3 quarts of the canned fuel on most saws.

especially is you live in an area where E15 is the norm

if you use more than a gallon of mixed gas a month and can find 100% gas 91 octane or better mixing becomes much more budget friendly.

one mucked up carb can make any savings mixing fly out the door.

my dad used have problems with his string trimmer , nothing but E10 can be sold in his county he would use at most gallon all summer , he uses about 2 cans of truefuel now and has not had issues with the string trimmer in a while.

I mix , but use a 2gallons or more a month most of the time and don't keep it more than a month

I use Startron also as well as 91 octane 100% gas form the separate hose at the station , I use the 2.5 gal pre-measured bottles I name brand only specifically for chainsaws ans string trimmer my dealer stocks them at a fair price dump bottle in empty gas can add exactly 2.5 gallons of gas right form the pump.

any saw is a bad batch of fuel away from being a damaged saw.
a good saw is enough of an investment and repairs are costly enough trying to save pennies on fuel can be a costly gamble.

I use a 2 cycle ratio cup to mix my 2 cycle gas with oil. Just go get 2 gallons of straight gas in a container the measure the oil I need shake and go.

I have been buying an oil that has stabilizer in it that you mix with gas or the pre-mix in the can that has stabilizer. I only use non-oxygenated gas on all my stuff like snowmobile, lawn mower, ATV, outboards, etc.

Non eth and any name brand Castor oil ( bean oil ) . The intoxicating smell is lovely . Reminds me back in the day when all the motocross tracks were nothing but 2 strokes.

I use non eth and Maxima Castor 927 oil in my sthil chainsaw and weed eater . Both get limited use and can sit for months. They always start right up

Yep , the " Ratio Rite " is your best friend