When mixing some oil for my weed eater, which is a 2-stroke engine, I didn't have enough oil, so I substituted some engine oil to make up the difference. Question: Why not just use engine oil? What is special about 2-stroke oil?
It's designed for the purpose -- mixes better and has additives specifically for 2-cycle engines. Primarily, also I believe is the lack of detergents found in 4-cycle oils.
2-Cycle is low ash (no pun intended) and engineered to be diluted in gas. Engine oil will leave deposits...and these may spark out the exhaust baffle. Using it once may not be problematic.
Years ago I had a couple of Saabs, with 2 stroke engines. I'm pretty sure they recommended either "Saab" 2 stroke oil or straight 30 weight oil as a substitute
Plug fouling. If you use motor oil instead of 2-stroke oil, you will likely foul the plug soon.
Back in the olden days you were told to use non-detergent 30w in your small 2 strokes and it will work but there are better oils these days (all the things the other posters have pointed out.) I bought a gallon of Quicksilver TCW3 for 12 bucks at Sams and that is probably a lifetime supply in my weedeater and chain saw.
The 2-cycle oil is formulated to burn cleanly; 4-cycle oils are not formulated with any consideration to how they burn, as they're not intended to be burned in normal operation.
nate
Quicksilver is a marine designated 2 stroke oil rather than a general purpose 2 stroke oil. I've used them interchangeably and never noticed any difference, yet manufacturers identify them separately. What is the difference??
-Red
Boat people will pay more?
Bingo! Engine oil is not designed to be burned! That makes more sense then anything else. Hmm...Question: I have a couple dozen small airplane engines, displacement .05 to .35. They are two stroke engines, and the fuel is methonal, optional nitromethane, and 25% oil, mostly castor oil. Castor is considered best because it does not break down under high temperatures, whereas the synthetic oil can burn or break down. If you have one lean burn, you can ruin the engine if you are using synthetic. If you burn 25% castor, the engines last forever. So, can I use castor oil in the fuel? I'm thinking not - I think the gasoline engines burn hotter, and I don't know how castor burns. More important - in the small engines, the castor is ejected from the exhaust and can make quite a mess. It would not be good to have hot castor oil dripping out of the exhaust.
That's the wrong oil. TCW3 is formulated for water-cooled outboard motors that operate at MUCH lower temps than yard tools. Yes, it makes a difference!
CWM
theres no difference,go ahead and use motor oil.
My Lawnboy is very particular in using its own oil. A gallon of other
2 cycle oil I was using was clogging it requiring a trip to the shop every year. A lot cheaper to buy the Lawnboy brand than a $50 to 80 annual service. Regular motor oil does have additives not meant to be combusted and will leave residues.Frank
And double the oil added, if using ND30 instead of two cycle oil. At least, that's what they say for chainsaws.
Years ago, I was told that marine engines are water cooled. They run about 100 degrees cooler, so they can use lower quality oils. Air cooled runs hotter.
It's not a matter of "quality", it's a matter of being formulated properly for the intended use. Lower engine operating temps present a different set of demands.
CWM
For some of the differences and background on the various classifications see--
According to Ook :
Castor oil was used in full size 2-stroke aircraft engines during WWI. One of the things that these pilots had to contend with was long flights during which being continually sprayed in the face with vaporized castor oil.
Hint: castor oil is used as a laxative.
Location of outhouses near the landing field was pretty important, but tends not to be mentioned much in modern accounts ;-)
One advantage of castor oil is that it's a plant product, non-toxic and biodegradable. Wikipedia sez:
Castor oil maintains its fluidity at both extremely high and low temperatures. Sebacic acid is chemically derived from castor oil. Castor oil and its derivatives have applications in the manufacturing of soaps, lubricants, hydraulic and brake fluids, paints, dyes, coatings, inks, cold resistant plastics, waxes and polishes, nylon, pharmaceuticals and perfumes. In internal combustion engines, castor oil is renowned for its ability to lubricate under extreme conditions and temperatures, such as in air-cooled engines. The lubricants company Castrol takes its name from castor oil. However, castor oil tends to form gums in a short time, and its use is therefore restricted to engines that are regularly rebuilt, such as motorcycle race engines.
Model airplane engines would be classified as "frequently rebuilt". I remember cleaning the gunk out of the guts of mine.
You'd probably find that using castor in a lawn mower would work great for a while, then you have to take the motor apart. And, not get too far away from a washroom...
I thought (but don't know) that most of the auto synthetic oils were castor oil-based.
You haven't seen some of the cars around here. I think they measure the oil use in MPGs ;-)
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