Stern tube and bearing help

NigelC

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May 1, 2015
1
Beneteau First 41s5
Beneteau First 41s5 (1989) New volvo 55 now with 150 hours. She has developed a major vibration in the driveline such that I cannot rev beyond 1500rpm. Upon investigation P bracket bearing within serviceable limits, so serious exercise of blocking off stern tube and undoing the dripless shaft seal to inspect the inner end of the stern tube as there is a fair amount of play at this end, what I find is there is no bearing at this end and certainly does not appear to be at the aft end of the tube. So current set up for prop shaft, is support at fwd end at the gearbox coupling direct to shaft then support at the P bracket. Questions, is this the standard setup or should there be an inner bearing? If standard the vibration has increased with engine hours, is this potentially due to engine beds settling in? Trying to do all this whilst she is in the water is quite entertaining but a great learning experience. Any information welcome, sorry if this has been answered before but the search function did not reveal anything.
 
Nov 24, 2012
586
Nigel some thoughts:

check out the cutlass bearing in the external strut. There should be no to negligible play when moving the shaft sideways.

New mounts shouldn't be a factor unless they were not properly installed and became loose. While I haven't done this you could disconnect the drive shaft coupling and see if you get excessive engine vibration.

Lastly has something changed in the shaft alignment and have you put a feeler gauge to make sure it's aligned correctly

Just some thoughts

TJ