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Is my set up optimal - ?

1967 Nauset with fresh bottom paint / one person / one 6 gallon fuel tank, see personal page for more info

2010 Yamaha 90 2-stroke mounted 2 holes up

Prop: Yamaha 13 1/4 x 17 inch Aluminum 6E5-45945-01-EL

At top speed the Yamaha tach is indicating 5300 rpm with one person aboard at 2 holes up.

When I switched from 1 hole up to 2 holes up, I noticed that I had to tilt the engine up quite a bit higher in order not to have lots of lateral spray coming from the cavitation plate while on plane.

At 2 holes up and on plane there is no cavitation.

Switching from 1 hole up to 2 holes up provided some additional lift in the bow.

Not sure if 3 holes up is smart? Might have to tilt the engine even higher? If so, will water cooling system work properly?

What about switching to a Yamaha painted stainless steel 17 inch prop? What sort of performance advantage might that offer.

Not sure about the speed at 5300 rpm. No speedometer. Still, its pretty fast into the wind with some chop.

Getting some more bow lift would be nice. I was thinking about moving the center console and seat back towards the engine about 6 inches or so. Lots of work. Good idea?

Any advice would be appreciated.

Thanks.

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Was the 5300 RPM WOT and trimmed out? If so you have a lot of room as I believe your RPM range is 5000 to 6000 and your at the low end of that. Lightly loaded you should be toward the top end of that range. I would not go 3 holes up, you need a different prop. I am sure Tom will chime in with the right model and pitch

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Yes, WOT and trimmed out.

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Geo, if finances is not a problem consider a stainless prop even at the (2) holes up O/B setting and especially if you can still go up one more hole position.

How far up (in inches) is the lower unit's cavitation plate from the keels center line?

A stainless prop will offer a bit better performance than the aluminum. Lets wait for Tom to chime in with a prop suggestion for you.