An example of two-stroke oil bottle with measurement cap. Oil is dyed blue to make it easier to recognize it in the gasoline. Because it’s not diluted, two stroke petrol engine pdf appears black in this bottle.
Unlike a four-stroke engine, whose crankcase is closed except for its ventilation system, a two-stroke engine uses the crankcase as part of the induction tract, and therefore, oil must be mixed with gasoline to be distributed throughout the engine for lubrication. The resultant mix is referred to as petroil. This oil is ultimately burned along with the fuel as a total-loss oiling system.
16:1 to as low as 100:1. To avoid the high emissions and oily deposits on spark plugs, modern two-strokes, especially for small engines such as garden equipment and chainsaws, may now demand a synthetic oil and can suffer from oiling problems otherwise.