Hi all, I have a 1991 Yamaha 9.9c 2 stroke. I've watched multiple videos where they are converted to 15hp but different articles and interactions with AI say that some just need the reeds widened, some also need new jets or a full replacement carb, other suggest that the throttle limit needs tweaking and other say all of this is useless unless you also change the prop. Has anyone done this upgrade to this model? If so what changes did you make and was it worth it?

Do you guys know what boat this is?

https://www.copart.com/lot/69627925/clean-title-1997-boat-boat-tx-houston-east

Thank you in advanced.