Re: fuel consumption A54

Porter McRoberts

Agree with Danny and Doug as well.
Our experience was the same: vibration means something is amiss and you need to investigate.  Use the comfortable bands of rpm to get where you need to go.  Malalignment leads to wear on the Vetus rubber coupling, which then leads to imbalance and further vibration.  In alignment it's completely obvious, smooth running over a wide ranges of rpms.  Also don’t forget the prop! 
A54-152 IBIS
Newcastle, AUS

On Apr 10, 2022, at 9:09 AM, Doug Smith via <dugsmith98@...> wrote:

Agree with Danny. 
My 54 had some vibrations at higher RPMs, above 1700. It was clear that something was out of alignment. After separating the Vetus coupling, my rubber donuts that dampen the shock loads were worn out. Replacing those and aligning and I was able to get to 3000 and yes, more noise, but vibration was still pretty mild and it felt like a boat at high RPMs. 
The prop can also do this and affect the RPM achieved. So can the turbo. But a turbo shouldn’t give a vibration that shakes the boat. 
Engine mounts, then Vetus coupling and alignment. Then at a haul out check the auto prop. There are email threads on each of these throughout the list serve. 
As Olivier showed me, when doing the survey on my boat, vibration can lead to a catastrophic failure of the drive train. Going at lower RPMs is a temporizing measure and has been successful so far but sometimes you need the power of higher RPMs and that will also be when it fails you. 

Thanks, Doug Smith

Amel 54-113, Aventura
White Point Marina
Kinsale VA, USA

On Apr 9, 2022, at 5:50 PM, Ralph Heilig <ralph.heilig@...> wrote:

Thanks Danny,

My engine gets louder as more rpm I use. If I sleep in the Master Room, it makes a big differnce it the engine runs with 1200 -1300 rpm or over 1800 rpm. I will try to get some dB measures this season. I thougt it is normal, that it's getting louder. It's new for me, that it should be the same noise over the rpm range.

I have to check...

Santa Isabella
A54, #144

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