I have a 1935 Evinrude 5hp Lightwin ( mod 4102) that does not seem to be pumping water. The water pump impeller is aluminum, and appears OK, yet there is no sign that any water is getting up the water tube to the power head. Compressed air indicates that the passages are clear. Does anyone know the proper orientation of the impeller (tips leading or trailing?) or if it can be converted/retrofitted with a modern rubber impeller?
Those antique motors had some very different water pumps. I think you must stick with the pump you have, but there are sources for water pump parts ... check with AOMCI.org I'd get a service manual outboardbooks.com I got one for my 1938 Evinrude Elto Pal for under $20. Motor rotation is CW viewed from the top, so pump is the same.
I don't respond to Private Messages PM's that are motor questions.
It appears I've answered my own question. Upon closer examination, I discovered that the water pump housing was not below the surface of the water. Raising the "tank" to remedy this, and water was flowing quite nicely out of the tell-tale.