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Message 4 of 4
Posted by member Paul Robinson on Wednesday 8 July 2015
Thanks Simon and Ray for your comments. I suspect a "singing" prop, as Ray suggests. There is no whine when in neutral or in reverse, and with the engine cover off and in gear at 1500 rpm if I put a metal rod to my ear and listen at various parts of the engine and gear box I cannot identify a whine, everything sounds normal. The whine starts at 1200 rpm, reaches a maximum at 1500 rpm and disappears above 2000 rpm. I suspect that the cabin is acting like a sound box, as on a guitar,and amplifying the noise. The frequency sounds around 100 Hz at 1500 rpm. The new prop was fitted by the previous owner just before I bought the boat. I think I am just will have to live with it, as it isn't very loud, and will run the engine outside the " noise envelope". Has anyone else had this problem?
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Message 3 of 4
Posted by member Ray Dubro on Monday 6 July 2015
Hi Paul,
When you have eliminated the easier options, bear in mind that it's possible the irritating whine may be caused by harmonics coming from the new propeller especially if the whine occurs at a specific engine speed.
The only cure in that case is to replace the prop.
Let us know what you find.
Regards,
Ray.
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Message 2 of 4
Posted by member Simon Papendick on Monday 6 July 2015
Hi Paul,
The problem could any number of things, did the whine start before or after the prop change. Have you looked around the engine cover to see if this is touching the engine. Any wear marks on the engine cover. This is where I would start first as you say you can not hear it when it is removed.
Other things it could be is a loose belt that is slipping.
I would look at these first.
Regards
Simon Papendick
Former Hardy Marine Employee
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Message 1 of 4
Posted by member Paul Robinson on Monday 6 July 2015
I have a slight whine from my Volvo saildrive on my Hardy 21 that I can't trace a reason for.It is at its worst at around 1500 rpm and can only be heard in the cabin. If I lift the engine cover and listen I can't hear it at all, it is mainly noticeable when sitting on the helmsmans seat. The noise is not very loud but noticeable. A new prop was fitted recently, could this be the trouble, or could it be the start of something more serious? Any ideas?
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