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AQ125270 Slow

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jamie392

Contributing Member
"I have an older 19' bayli

"I have an older 19' bayliner capri that I have been fixing up. The engine seems to run really good, no hesitation, idles smooth and runs right up to 5500RPM without hesistation.

The boat is rather slow though. I think at 5500RPM it is toping out at 25MPH. Is this normal?

The prop is a 14*15, maybe a little too small of pitch I suppose, but even at that I think it should be better... I'm thinking about putting on dual carbs, is there anything else I can do to boost HP and speed."
 
The easiest solution would be

The easiest solution would be to buy a new boat.

I have a 19' too. These old bayliners are not quick at all. I do about 28mph up top and I have the 225HP version with a 15x19 prop.
 
"Boats not like cars...takes l

"Boats not like cars...takes lots of HP to push them along. The maximum RPM on the AQ 125 per the volvo website is 5000 RPM. The HP is 117.
Your 14x15 prop is a bit small as WOT (Wide Open Throttle)RPMs should not go that high. Going to a 14 x 17 should drop your max RPMs to about 5100 which is better. You should also see a slight increase in top speed as well as cruise. For maximum engine life, you should probably limit continuous (cruise) RPM to 75 to 80 % of RPM at WOT."
 
"Thats kind of a bummer to hea

"Thats kind of a bummer to hear... And I can't afford a new boat.

Since I have a 19 footer or so 1985 Capri I am working on with that same engine/IO combination, is there anything you can do to up the top speed a bit? 35 would be nice. Heck, a true 30. ;)

Is HP the only answer? Could one sculpt some new foam and glass on the hull.
Make it a newer vintage, hydro-dynamically?

I have an 18 HP Briggs and Stratton and a 40 HP Johnson I can tack onto outriggers, maybe those will help. Will look funny, but a tri-engine tri-hulled Capri would be unique. And I can make a fake case for the Briggs so it looks symmetric. I'd have to name the boat "Only In Circles" though. Maybe a balsa interior will help a bit. Mesh outdoor seats from Wal-mart to lighten the load further?


(Seriously : Thanks for those tips on the RPM and prop!)"
 
"Robert, the owner before me h

"Robert, the owner before me had a 21 pitch prop on there and with that prop i could do 30+ at 4000 RPM but... it wasnt as good for pulling a wakeboard or hole shot. I think 17 or 19 pitch is probably best."
 
"Thanks for the pitch info. I

"Thanks for the pitch info. I am a boating newbie for the most part, and this is a project boat, so my discoveries will be in the future as to actual performance , that is, if the engine is truly in good condition as they said.
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It will need a prop if it all works out as the aluminum one it came with is junk, one blade has a strip torn at the end. I will likely start with the 17 pitch and see how it goes. The boat will be used for skiing and cruising, I've read that's a good compromise pitch."
 
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