Re: [Amel Yacht Owners] D3-110I-C Wandering RPM

ngtnewington Newington

Hi Porter,

I watched the video that is a massive reduction in RPM. Is their black smoke when it does that because it looks like the engine is seriously overloaded and about to stall?

So the fixed blade prop stops it right. Therefore there is nothing wrong with the engine itself.

Thus it must be something to do with the Bruntons Autoprop, which is a variable pitch prop.

The pitch varies automatically in order to maximise efficiency. "The Autoprop blades, unlike those of conventional propellers, maximise the thrust delivered whatever rpm the yachts engine is running at “

quote from Autoprop website.

So if the thrust  is maximised at all times then load on the engine must vary a bit. Just like say the big alternator kicking in when one runs a heavy load off it, say a toaster for example. So I would expect a slight variability in the rpm as the load on the engine varies but not like in your video.

Agreed there is something wrong with the prop. You could strip it down yourself, it is pretty easy, before returning for service.


Amelia (Amel 54 019) back at home for a bit.

On 30 Aug 2018, at 10:44, trifin@... [amelyachtowners] <amelyachtowners@...> wrote:


Wow, that is a pretty major "wander" in the video, so glad to see it was resolved by changing prop.  
Your numbers look ok, except for WOT 2200 seems awfully low. I think you do need to follow that up with Volvo, particularly with the fixed prop now in place.

I checked my WOT this morning in flat water/no wind and it was stable at 2920rpm.  

I also took a short video of the wandering I was referring to, its in the" ZF25 Transmission" folder in the files section.  It shows a variation from 1170 to 1210, difficult to hear the engine note on the video, but 40rpm variation is just enough to make the ears prick up!. Given yours and Mohammad's observations, i'll put it down to propeller effects.

I've also uploaded my Sea Trial results from a few weeks ago after we had the gearbox fitted.
It was a bit choppy and breezy, so the speeds are a bit lower than we get in flat water.

Danny, and others - I've solved my oil leak.  Not sure exactly what to attribute it to.
I found an extra 1/4 turn on one of the fwd end sump bolts, but I've also done my regular oil/filter change including replacing the Oring on the oil filter cap.  One of those things solved it - I suspect the filter cap may have been the culprit.   

SY Stella
AMEL 54 #154

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