Home › Forum › Ask A Member › bigger carbon 18hp 1959 evinrude help › Re: bigger carbon 18hp 1959 evinrude help
August 23, 2015 at 5:08 pm
#22522
About the only wAy you can get more power out of that motor would be to swap a late 1960s 25 hp powerhead onto it, carb and all. It’s the same displacement as your 18, but has different pistons, crankshaft, head, porting, etc. No, it is not easily possible to convert your 18 to 25 specs.