I bought a new to me 1979 Evinrude 85 and after succesfully rigging the motor and running on the lake, I discovered that in idle at neutral, I sometimes get the overheat tone on the alarm buzzer. I bought and attempted to replace the water pump impeller, wear plate and the housing.
I notice there's slight differences between the original and the aftermarket (Sierra) housing.
My concern is the mechanical seal at the top of the housing. Is this not required anymore? It was not included and there's no spot for it anyway. Check out the pictures:
Replacement Sierra aftermarket housing:
Another picture showing restriction caused by burned plastic: