Engine vibration mystery: Part2

[rays]

Further to my earlier post and helpful replies. The propshaft has just been given the OK. The prop likewise. So the problem must be alignment and/or engine mounts. On Friday we are putting the shaft back. Will the engineer be able to set up the alignment with the boat in a cradle? I've noticed that a couple of locker doors are tight so presume there's slight flexing whist in the cradle. Will this bugger up the alignment set-up?

 

[NorthUp]

If the doors were free while the boat was afloat, then yes.

 

[sailorman]

the boat also srinks in cold weather this would also cause locker doors th bind-up

 

[Ceirwan]

Get it right out the water as a base to work from, and then realign once back in.

 

[sailorman]

i dont have a problem

 

[Ceirwan]

Sorry mean't that as a reply to the op.

 

[alexrunic]

sorry but i didn't see your first post. engine alignment should be finally checked / adjusted when on the water i noticed a small difference after fitting a new engine from checking on the hard standing to being afloat.

 

[MidiMagic]

Hi
I replaced a BMC 1500 engine with a more modern one and carried out the final alignment on the water as even the strongest built boats flex when on the hard.
The shaft slip straight into the coupling and I was really chuft so off we went for a test "drive" and OH! the vibration. Turned out to be the engine mounts, which though new and bought to make the engine fit exactly as before, were just not upto the job, being too"stiff" I was told. replaced the mounts and perfect there after. Your engine manufacturer can supply you with details of best mounts.

 

[Refueler]

One engine mount went on my old engine ... that was teeth shattering bad !! But a bad mount can cause all sorts of vibs from small amount, to only at certain revs ... to my shattering !!

 

[TigaWave]

Are you going to check the bearing and bearing carrier alignments?

If you have a stern tube cutless and p bracket cutless it is possible that these are not in alignment. Before starting to set up the engine to shaft alignment the bearings/shaft alignment needs to be checked.