Here is an interesting chart. I compared the speed vs RPM of the 'standard' CY338 Outboard (Bracket) with my boat CY338 with extension bracket . . . I used the data from BoatTest done back in 2019 when the OB version first came out. The stock OB had 350 HP Verado engines w/16x18 props. My boat has the 350 HP Honda w/ 16x19 props.
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This chart really demonstrates the benefit of the extension, as can be seen in the separation of the performance lines in the 2,000 - 4,000 RPM range.
There is still some testing and tweaking to go in order to get the Honda up closer to 6,000 RPM. I'll be interested to see how it all translates to mpg's
