SunsetB

Hi,

I write from Italy because I have some problems: my boat is a Wellcraft 23' Nova by single engine (Volvo Penta AQ271 Duoprop, year '87). The maximum speed is only 40 Mph, but the old proprietary tell me that the boat must reach 52-53 Mph. I think to have some engine problems.
Which is the maximum speed of your 23' Nova (by similar engine: single 260-300hp)?
Thank you very much

Emanuele

PS: My propellers are the B7 by Volvo Penta and the engine reachs only 3800rpm instead of 4400-4600 that is the correct range

GoCiggie31

last year I had a 23 nova purchased new in 86 with a 454 alpha (1:32 gears) installed 365 mag crane cam, cmi headers, alum manifold ported heads, 810 holley, lightened up interior cabin, no windshield and would do 64 mph in salt light chop...great boat had for 18 years and was a great family sport boat.

resurrected

I had a 23' Nova last year, only had it for the one season so I don't know a lot of the specs. It had a 350 MAG with alpha drive. On calm fresh water the best I was able to get out of it was 45-47 MPH on the gauge. GPS I don't know! In 2' waves I was able to see 50-53 MPH on the gauge. Sorry this is all I can offer you, I don't know anything about Volvo drives.

Whiteknuckle

SunsetB
I would think that your current speed is not to far off. I would guess low 40's would be what you should expect. An honest 50MPH I think is unreasonable to expect. Check to see if your engine is pulling the RPM that it should most likely about 4800. Make sure your props are in good shape, and the bottom of the boat is clean. Then if your still only getting 40 MPH, don't worry about it.

Kidnova

It would help to know more about the engine you have. What is the displacement and horse power? Nova's are heavy boats for the length. Mine weighs in at 4000 lbs. With the old 330 hp 7.4 {454 CI} it would do about 56 on gps.

If you're in the 260 hp range and have a Duo prop set up, I think Whiteknucle is just about right regarding low 40's.

cooltoys61

He said 270HP. I think you should at least check to see that your total spark advance is where it should be,,if thats correct then maybe smaller props so you can hit your upper RPM range. I was just in Italy and spent a week in Moneglia(with a walk through the cinque terre and Portofino),,it was awesome, also spent 3 days in Siena and 2 in Florence,,what a nice country!

Hydrocruiser

It's about a 48 mph boat with that power in fresh water.

Have the engine compression tested and gone over...check the dirve...you should have a 18-21 pitch Mirage on that I would think as a friend did for best overall performance.

Whiteknuckle

He has a Volvo duo-prop, not a Merc! That is a big boat to be getting 48 honest MPH out of. That 270 HP 350 is a great engine, but a performance engine or BB it's not. I still say low 40's if everything is correct. The key here is if the engine is pulling its rated RPM.

madbouyz

Personallly, I'm also with whiteknuckle on this.
Even if the boat was turning up max rpm I can't see much over what your getting now .

The only thing I would strongly suggest is having your tach
checked for accuracy (most of them are able to be calibrated).

I've had a few tachs read wonky on me and nothing can fork your head up faster.

SunsetB

My engine reachs only 3800 rpm and the installed propellers are the B7 by Volvo Penta.
Volvo tell me that the correct range for my engine is 4200-4600rpm. I think, if the engine is ok, that the props are not for my boat.
Some people have sayd me that by 260 hp Mercruiser the Nova 23' reachs 50 Mph, is it possible? Can steel propellers improve the performances?
Do you know some internet sellers to buy new genuine Volvo propellers at human price?
Thank you very much!!!

Emanuele