Hi, I've just bought a Mariner 8hp sailmate 2004, and I've been told that the engine is the same for 6, 8, 9.9, 10 and 15hp versions. How do I go about uprating to a 15hp. I presume I have to adjust the carbs or fit new jets but am not sure...
Maybe post over on the Honda/Tohatsu/Nissan board and you will get a better response from those who work more with that motor since they are all (small Mercury engines) made by Tohatsu.
Do you think it is likely that you could nearly double the HP by making some simple change? If, in fact, the base block is the same it is probable that everything else is different, including the bore and porting of the block.
It would probably be cheaper to give the 8HP away and go buy a 15.
