Conventional 2-cycle (2-stroke) engines need oil in their gas to provide lubrication. This simple calculator tells you how much oil to mix into gasoline for a 50:1 or other mix ratio.
Which mix ratio?
Most 2-cycle engines work best with a gas-to-oil mix ratio of 50:1 when you are using a high-quality 2-cycle oil. Most recent 2-cycle oils that are synthetic, semi-synthetic or enhanced with additives would qualify.
| Engine | Equipment | Oil type | Mix ratio |
|---|---|---|---|
| 2-cycle, air-cooled | chainsaw lawn mower leaf blower weed eater | synthetic, semi-synthetic, additive 2-cycle | 50:1 |
| mineral oil | 25:1 | ||
| 2-cycle, water-cooled | outboard snowmobile | 2-cycle TC-W3 | 50:1 |
| 2-cycle, autolube | scooter motorcycle | no oil to gas | N/A |
| 4-cycle | car snowmobile | no oil to gas | N/A |
If you are forced to use a low-quality oil, you may use a thicker, oil-richer mix ratios such as 25:1 and 33:1. The table above gives you an overview of the proper oils and mix ratios for different engines.
Note that 4-cycle engines and 2-cycle engines with an auto-lubrication system take pure gasoline without oil.
For more info on mix ratios, check my recent article on the topic. To know if you should buy pre-mixed fuel, see my other article.
