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S&S Swan Maintenance - Vibration / knocking at rpm over 2,000
19 May 2013 - 08:02
#1
Join Date: 16 April 2010
Posts: 36

Vibration / knocking at rpm over 2,000
Ourtageous (swan 47#039) is experiencing a knocking at rpm over 2,000 (and under when in a cross sea). I suspect cutless bearing. Does anyone have any views? Insofar as you agree with my diagnnosis can anyone tell me the shaft diameter ( I am in Switzerland and Outrageous in the UK) and also the layout of the cutless bearings (1 or 2?)
Thanks
Mark

19 May 2013 - 11:18
#2
Join Date: 02 January 2008
Posts: 1547

Dear Mark
The reason could be either a worn Cutless bearing, or the shaft touching the stern tube wall where it passes through the hull. Loud sharp knocking would indicate the latter.
As the engine has been replaced there may be changes to the original installation, and it is necessary to confirm things on board.
Original shaft was 1.5" with one Cutless bearing.
If the shaft touches the stern tube the engine rubber mounts need adjustment. It should be checked that the shaft is in the middle of the tube by dismantling the shaft flange from the gear flange, and lifting it up and down in order to find the middle. Then shaft and engine to be aligned in the new position.
Kind regards
Lars

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