replace the 9.9s

Post here for issues with outboard engines (i.e Yamaha 9.9) on PDQ yachts
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replace the 9.9s

Post by wake up »

just saw the spec sheet for the new yamaha high thrust 25hp with a 30 inch shaft. Who is going to be the 1st to try to fit them?

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Re: replace the 9.9s

Post by Lady of the Lake »

Will it fit?
Sam and Gina Densler
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Re: replace the 9.9s

Post by Cat Tales »

Looking through Yamaha's website, I couldn't find the 25hp with a 30" shaft. They only had data on the 15" or 20".

Powering through current and head winds with decent speed would be a great advantage over our current 9.9's, but what do you think our new top speed could be pushed to with the 25hp's?
Chris & Kelly Haretos
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Re: replace the 9.9s

Post by Lady of the Lake »

Still not convinced they will fit and will be too heavy...
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T25 Yamahas

Post by Page 83 »

I'm disappointed that Yamaha lowered the gear ratio on the T25 compared to the T9.9: its 2.42:1 rather than 2.92:1, You will notice that on the pontoon boat example, it tops out at 5178 rpm and 12.05 mph, but the engine needs to get to 5500 rpm to put out 25 hp. I'm just guessing that its developing 19 or 20 hp at that rpm. While thats twice what we can get from the T9.9s, its also twice the weight (or more with the long leg and power T&T!) Roughly scaling up the brochure drawings makes me suspect that this engine is too big from the tilt hinge to the back of the engine, and it won't have room to raise out of the water without cutting away part of the aft cross bulkhead (a major structural component) and raising the height of the engine hatch, a scary thing to consider.
If they make a lower pitch prop available, allowing the engines to reach full power at ten knots, they would certainly be worth considering; the fuel economy is good. This is really a wild-assed guess, but I think we could see nine or ten knots with a pair of these engines, and a lot of thrust to punch through wind and waves.
These might be just the ticket for some bigger cats, say in the low 40's LOA and under 12,500 displacement. But they weigh the same as the venerable Honda BF-50, a three cylinder engine.

I just wish they'd check with me before they make all these mistakes! :lol:
Sandy Daugherty "Page 83" PDQ 36026
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Re: replace the 9.9s

Post by wake up »

Cat Tales you are right i misread the sheet, it has a model no for the 30" shaft but its not offered.
I tried to post the model sheet but apparently the forum does not allow .pdf files.
I posted a photo of steel sails instead. That didn't work either. ".jpeg" What files can we post?


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Re: replace the 9.9s

Post by Lady of the Lake »

.jpg will work, .pdf you have to email to me at sdensler@mac.com and I will post them on www.pdq36.com

Sam
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