I removed the power head on my Johnson A-80. The gasket was destroyed so I made one as close as I could reconstruct from the pieces. There are four small holes in the housing, two on either side of the drive shaft. The old gasket just covered them near as I could tell. It seems to me that there should be 4 holes in gasket to allow whatever to pass from head to housing.
I just went through this a month ago. Wish I could say I remembered
for sure, but it seems like if you examine the power head, that only
one drain hole is actually in use.
Look up in all the cavities in the power head. I think only
one has a drain passage to the crankcase.