I have a 1995 C75. Several years ago I was at a repair shop and an old mechanic told me that Yamaha actually offered kits to upgrade motors and increase Hp. He also said this would not void any type of warranty since their tolerances are so tight. I know that this is probably possible to do even if a kit isn't available but my question is would it be worth the expense? I know those two motors have the same stroke and bore so woule there be anything else involed besides rejetting, different intake and different Head? The only reason I'm even curious is I purchase my boat and motor as a package. It was said to be able to turn out about 40 mph. It has barely ever seen 30 mph. I'm not into the race seen but it would be nice to have a little more get up and go. This motor has never even tached up to factory recommendations only around 5000. The prop is the same as factory specs and I have even had the cup taken out but it didn't help. I'm just curious to see what options I might have.
