[SPLASHED] I/O (Sterndrive) Conversion to Outboards

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Looks great, I'm still getting used to yellow "ground" wires lol.
https://www.electricaltechnology.org/wp-content/uploads/2020/07/ABYC-Cable-Wire-Color-Codes-for-Yacht-Boat-Marine-Wiring-768x674.png
 

tpenfield

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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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Merc-vs-Honda-1AA.png
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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
 

Pmt133

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Two questions.

Do you think the the apparent (I say that only because of the lack of top end RPM in current configuration and any number of things can help correct it) slight over proping of your current setup is also helping your low speed planing? I've seen it go both ways with that.

Do you think if you end up adjusting height for RPM that you'd lose some of the low speed planing. Again... seen it go both ways.

Outside of some really trick setups or setups with a lot of tab, there arent too many vessels I've run or seen that can both get on and hold a plane at 18 mph. It's quite impressive. I can do it on the 4winns but you need to constantly adjust throttle because it's the edge. That's also about 1/6th the boat you have. :p

I suppose a third question but this isn't really related to your vessel... do you think the factory OB model could be improved with a different prop selection? I've got to assume they're running the enertia on that. On my hull I needed about 4 extra (22 mph) to get on plane with the enertia. While I don't think in this case it would help, you can't help but wonder.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Wonder what your curve will look like with 18p props
 
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