why do you have to mix oil and gas in a two stroke
Two-stroke oil 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.[1] The resultant mix is referred to as petroil.[2] This oil is ultimately burned along with the fuel as a total-loss oiling system. This results in increased exhaust emissions, sometimes with excess smoke and/or a distinctive odor.