Re: 1951 Evinrude M4443 7 1/2 hp

[fisherman6]

Hi Dale,
There is no lower crankshaft seal below the crankshaft on the bottom of this engine. Like my ’54 SuperFastwin the bushing and the oil film do the sealing duties. It appears there is a place for a seal similar to what you found in your engine to seat between the crank throws inside the crankcase. There is what appears to be a seal bore on the lower side of the center main bearing. Presumably this is to prevent pressure pulses from escaping top to bottom inside the crankcase. What I don’t understand is how it could go in there unless it is not a continuous seal.

I believe that woodruff keyseat looking cutout in the crank at the lower main journal is what pushes the lube up the pipe that connects the upper main to the lower to keep the upper main bearing lubricated. Someone will correct me if I’m wrong.
-Ben

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