Re: 63 Evinrude Lark 40 hp - oil in exhaust
You have to believe it. It is normal. Yes, getting it out and running it will clean it out somewhat, but more still comes.
It's time for a short explanation:
All two cycle engines waste a lot of fuel which blows out the exhaust ports. Some are much worse than others, but they all do it. Unless you have a new e-tech, I guess.
In all two cycle engines (again we aren't talking about new e-techs) the fuel and air charge passes through the crankcase on it's way to the cylinders. There has to be room in the crankcase for the crankshaft and connecting rods to whiz around. That means the fuel/air charge slows down as it goes through that big space, especially at low rpms. The slow movement allows droplets of fuel to "rain" out of the charge and settle in the bottom of the crankcase. That settled out stuff would cause lousy running if it were allowed to go on through in liquid form. So what they did on most older engines was drain it off somehow and dump it into the exhaust stream, and ultimately into the lake.
OK, I agree it wasn't too nice, but the truth is the truth. Beginning around the 1970's people started becoming more concerned with the environment and mfrs started devising ways of capturing that wasted fuel and burning it. Also, a side effect of the horsepower race was that the crankcases were made more efficient, thus less "rain".
Yes, newer motors still create an oil slick in the water and spots on the driveway, but nowhere near as bad as the old ones.
Running in a barrel or bucket makes it appear much worse because it is concentrated and emulsified in the water.
Use full synthetic TC-W3 for less smoke and slick on the water and better bio-degadeability if you care.
Edit: Guess I should mention that the oil you put in the gas is not all burned. It wouldn't lubricate the cylinders properly if it did. So, the unburned protion also blows out the exhaust. The burned portion is the smoke, the unburned portion contributes to the slick.
