Turning a 9.9hp into a 15hp outboard. Actual GPS results. Is it worth it?

Swapping a 15hp carb into a 9.9hp Johnson outboard.

[@dentalnovember]

I would love to have this motor. These gems are tough to come by.

[@mikep303]

That's one way to make your johnson bigger😊

[@outboardfun3353]

You have also change to the turned exhaust tube that 15hp has. If you put more gas in you have to gas more exhaust out also to be 15hp

[@jnljnl8485]

What's next? Cut the cylinder to set squish and some porting? 😂

[@danblanchard9145]

Did you swap out the prop as well to account for the extra horsepower? I’m thinking that a 33% increase in horsepower would require more pitch at the same RPM.

[@07slowbalt]

Kinda surprised me how well that thing moves for such a small motor

[@gioscervelo]

That's about right. My Evenrude went from
9.9 hp 30 kph
15 hp 35 kph.
My 15hp Nissan goes 40 kph

[@jadenporter3975]

Where did you find a carb I have same year motor I’d love to do the swap but can’t find a carb

[@allyoucancatchoutdoors6898]

Yea where can we get the carb from?

[@mikeeiben3430]

Ill it troll as nice with the larger carburetor?

[@ct1762]

no definitely not!

[@ericbullock3188]

i was told you can do the same with a mercury .