Yamaha 15hp -> 20hp
Been searching on some tech info on my recently purchased 2007 Yamaha F15.
From what I can see. The 20hp is the exact same motor.
Found out some differences in carb jetting. But from my knowledge air needs to be added to compensate for the richer mixture. In order to achieve larger hp.
Is there any knowledge on this form regarding this topic?
In my opinion, either the exhaust needs to be opened up or the camshaft is different. Since carb and intake mani are exactly the same.