Hello again. I'm also working on a1972 Evinrude 4HP direct drive. It over heated a week ago, and stopped running. I replaced the impeller, but it still doesn't seem to pump much water and overheated again yesterday. Can the cooling channels in the engine be clogged? It is a salt water motor and I haven't been to good about flushing it over the years...What else would make it overheat with a new impeller? Thanks