Reply To: 1953 Johnson Seahorse 25 hp RD-15 not pumping water

[Don]

I have no experience with this model, but a few things concern me….. First, like Frank says, that impeller key should not be able to “fall out of place” once the impeller housing is properly installed. So, if the key is falling out, something else is wrong. The other thing that concerns me is that you are talking about flipping the SS impeller plate upside down on the gearcase. There is only one way that SS plate will work properly, and I have never seen an OMC that has symmetric screw holes in the plate, so it seems almost impossible to successfully install the SS plate upside down. But again, I have never had any experience with this particular model…
From what I have read, it seems like you got this engine with the cooling problem, so it is not something you did….I’m guessing there is a mismatch of parts also….Hopefully Frank or someone will chime in to confirm whether or not the SS plate can be inadvertently flipped upside down on this engine….