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