Last night while motoring back to the marina, I ran over a motorboat wake. This caused the prop on my 8 hp Nissan 2 stroke outboard to briefly break the surface. Of course, the engine raced when the prop came out of the water, but the engine also began to smoke quite a bit. This had never happened before during similar incidents. Normally, the engine exhaust goes out underwater, but there is always a little exhaust visible around the shaft. After the cavitation, there was a lot more than normal. I immediately throttled back and let the engine run at low rpms for a minute or so. The smoking eventually dissipated, and when I throttled back up, the amount of visible exhaust seemed to be normal. Any thoughts on why this happened?
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Steam?
What color was the smoke? Could the lack of cooling water have caused steam to form (or worse, your impeller started to melt/burn)?
What color was the smoke? Could the lack of cooling water have caused steam to form (or worse, your impeller started to melt/burn)?
Probably just lubeoil on the walls 'shaking loose'
With oil mix fuel in a 2 cycle most of the time the lube oil thats in the fuel will adhere to the walls and internal surfaces, and if you shake or over-rev a 2 cycle this oil will come loose, enter the combustion chamber .... hence the smoke, until it clears. Usuallly nothing to worry about. Same thing happens if you idle for long periods of time and then 'gun' it.
With oil mix fuel in a 2 cycle most of the time the lube oil thats in the fuel will adhere to the walls and internal surfaces, and if you shake or over-rev a 2 cycle this oil will come loose, enter the combustion chamber .... hence the smoke, until it clears. Usuallly nothing to worry about. Same thing happens if you idle for long periods of time and then 'gun' it.
Thanks!
thanks for the input. While I understand how my engine works, I'm no mechanic. Appreciate it.
thanks for the input. While I understand how my engine works, I'm no mechanic. Appreciate it.
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