Actually, it is possible. I mix gas/oil for my weed wacker (yes I occassionally use TCW3 when I don't have the other 2 stroke oil around) about 16 oz at time by pouring in the correct amount of oil into a small marked bottle, then pouring gas on top of it. The oil pools at the bottom - definitely not completely mixed. I have to swirl the container quite vigorously to mix it up. There is no doubt in my mind that the fuel at the bottom is much richer than the fuel at the top unless I mix it well. <br /><br />On the other hand, I do believe that if you pour oil into a normal gas can, and fill with gas from the pump, it will mix well from the force of the pump and you don't need to shake it up.<br /><br />When I premix in my large tanks on the boat at the gas station, I make sure I spray the fuel from the pump around towards the bottom of the tank where I poured the oil. When I fill the tanks from 5 gallon cans, I tend to pre-mix in the can to make sure it gets mixed up.<br /><br />I don't think oil mixes quite as perfectly and effortlessly as people think. I'd rather not leave it to the mixing motion of trailering the boat or running through the waves. I have no evidence it doesn't mix it up though.
