OK, this may seem a little naive, but its never occured to me until now. Is two stroke oil all the same? I have a Craftsman chain saw that uses a 40:1 mix and a Stihl edger that uses a 50:1 mix. I've run out of the 2.6 oz. oil containers that I've been using in my old 50:1 edger/trimmer. I have Craftsman two stroke oil in 3.2 oz. containers and it states that its for 40:1 mix. Is the Craftsman oil just labelled for 40:1 because of the amount in the container and it would be safe to use it in the proper ratio of 2.6 oz. per gallon in my Stihl edger? If so I can just dump 3.2 oz of the Craftsman oil into 1.25 gallons of gas. I rarely use my chainsaw and figured I might as well use up the oil I have for it before buying more if I can.
Question about two stroke oil
- Thread starter Oddball
- Start date
Other than synthetic vs. dino. there are two types of 2-stroke oil, one for air-cooled engines and one for water-cooled. You don't really want to interchange those because air-cooled engines can run very hot and water-cooled ones, especially older outboards with no thermostats, can run below optimal temperature. Also, engine manufacturers will specify the mix ratio, usually with a specific recommended oil, whereas many oil manufacturers, particularly synthetic, will leaner ratios, claiming their oil is "superior". Unless you want to experiment, go by what the engine manufacturer recommends.
reynoldston
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When I was young and living on the farm (40's) as I remember in all 2 cycle engines my father used non detergent 30 oil. They cut a lot of wood with big 2 cycle two man chain saws. Then in the early 60's when I first stated riding 2 cycle engine snowmobiles I used 30 non detergent oil. I never had any engine problems other then I used a lot of spark plugs. Bought spark plugs by the case. Then they started to come out with the 2 cycle oils and the spark plug troubles went away. Now this pass summer I was talking with a older person that heated his house with wood. I got talking with him about oil and he told me that the only oil he ever used in his 2 cycle chain saws was 10W30 car motor oil. Myself I use the proper 2 cycle oil in what I am using just because I don't want problems and it just doesn't cost any more and also I think it has to be better for the equipment. But as I see it it really wouldn't matter what 2 cycle oil you used as long as it mixes with the gas, needed oil in a pinch or wanted to use something up. The only time I real ever had a 2 cycle engine burn the piston up was when the engine was running with the fuel mixture too lean not the wrong oil.
Wow, thanks for the history lessons in 2 stroke oil. So they actually came out with the engines before the 2 stroke specific oils to use in them? Well, on second thought I guess that makes sense. Just out of curiosity what happens if you run a higher oil content mix than required, i.e. 40:1 in a 50:1 motor? Will it just not run as well and foul the plug or will it likely damage the engine?
Not only can running a richer oil ratio foul the plug(s), it also leans out the fuel ratio (less gasoline to air). That can cause overheating and detonation. So, it's not a good idea to use more oil "just to be safe".
I have thought about that and has brought up at my engine update meetings but lets look at it in another way. Doubling the mix ratio say from 50:1 to 25:1 only makes a 2 % change in the amount of gas being consumed. If 2 % is enough to cause an engine to run lean and overhead I would think you already have a problem with the engine.