Welcome! Need support, you got it. Or share you ideas and experiences.
In Reply to: Johnson/Evinrude 9.9 to 15 hp conversion posted by DB on March 04, 2002 at 12:21:07:
Well your right on more than one count! The Johnson/Evinrude 10/15hp are the same except for carburetor, slight port/timing changes and the majority of the boost to 15hp coming from the tuned exhaust system on the last 10% of the throttle twist. Johnson built--up to a few years ago--a mini hydro ‘racing’ version of the 15hp motor. Aside from the radical lower unit and prop it seemed to be mostly a highly tuned exhaust system that gave this motor it’s 'zing'.
Sorry, don’t have any info. on converting the 10hp to the 15hp though…
This post is made possible by the generous support of people like you and our sponsors: