Hello everyone. I just picked up an older Evinrude looks good but will need some TLC, plugs ,points new lower unit oil etc. The cowel cover says Evinrude 25 and looks like the color scheme of a 1971. The model number plate reads 18602C-E13799. I know this is a 18 hp 1966 number. The previous owner did not know much about it. They aquired it used about 5 yrs ago. I want to make sure I get the right parts when ordering. I can tell work was done on the powerhead ( paint is cleaned off and gaskets are newer ) I suppose its possible that someone put a 25 hp power head on a 18 hp base. Is there any way that i can ID the power head . The numbers on the engine plug are 385440 RPH. Thanks for the help.