Re: The evinrude 9.9/10hp carb change to make it a 15hp urban legend.

[r-c]

Those 9.9 and 15’s had so many changes through the years it is hard to keep up or even remember all those changes. 1974 to 1993? Before the bigger 15 cubic inch model.
There was a time I think in the early models, it was just a smaller carb. When they went to the actual tuned exhaust, which really helped the mid range, it was not only a carb change but the cylinder head also had less compression than a 15.
When we had the Evinrude dealership and there was a near by lake restricted to 10hp or under. We sold a lot of 15’s and bought 9.9 hp decals. That was until "aqua fuss" got smart and learned the model numbers. We had to go back to the parts book and figure what we needed to make a 9.9 into a 15. Cost was pretty expensive to the customer. But the customer is always right.