Could it be the gearbox!?!?!

[SteveB_Sigma33]

Well I,ve just come in from my first shake down sail of the season.

Cracking time whilst under sail, but scary time whilst under motor!!

I seem to be getting a strange grumbling sound from within the boat. It's not the engine as when the boat is out of gear she is as happy as a lamb!

Decided I'm going to investigate further tomorrow by disconecting the prop shaft from the gearbox and see if I get the same grumblings, however!!!! Do people want to scare me stupid with their gearbox stories? It may help point me in the right direction.

The engine is a Volvo Penta 2002 (yes I'm aware of the spline problem, but this usually has no characteristics before a failure so I'm led to believe).

Symptoms are :-
Forward and reverse motion is good (apart from the grumbling)!

There is oil in the gearbox.

Doesn't always make the noise.

Any horror stories or suggestions!

Thanks in advance for either

Oh! and just one other thing, any one have a Scooby how much a reconditioned gearbox would cost if needs be! Just aswell make myself completely miserable in one hit!


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[chriscallender]

Perhaps something caught around the prop?

Chris

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[boatless]

Cutless bearing in the p bracket?

<hr width=100% size=1>my opinion is complete rubbish, probably.

 

[Mudplugger]

Engine gone out of alighnment??, can happen if out of water for length of time. might be worth checking. Regards Tony W.

<hr width=100% size=1>Tony W.

 

[boatmike]

I used to have a grumbling noise from within the boat but I now sail alone and it has gone!

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[theia]

have you got an anode on the propshaft? if so, has probably come loose and just needs tightening or replacing

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[jonjo]

Try a few more turns of the greaser. If the noise goes away for half an hour this indicates you need a new stern gland but hopefully not a replacement for a worn prop shaft.

Alternatively could it be over winter damage to a prop blade that is now triggering cavitation?

> any one have a Scooby how much a reconditioned gearbox

Try and live with the problem until you can do the whole job properly i.e. fit a Halyard Aqua Drive and new engine on soft mounts. The investment should add value to a desirable used yacht such as a Sigma 33.

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[jeanette]

I had a similar noise to diagnose a few years ago, it turned out to be worn bearings in the aquadrive on the prop shaft.


<hr width=100% size=1>Jeanette

 

[mldpt]

I have a problem like this and I am sure its the shaft catching the Stern tube useally caused by poor alignment of the engine and Gearbox to the shaft. I have renewed the engine mounts a few times and always managed to get the alignment ok but since I replaced the cutlass bearinf last year I just cant get it right, Mine is OK uo to 2000rpm unless its rough and the boat is being chucked about a lot but increase the revs beyond 2000rpm and it starts its like a very quick nocking very sharp.
have you cured yours yet.
Mine is on A Westerly Corsair volvo 2003 which runs a treat I put new mounts last year and I recon they are worse now then the ones I replaced with them.
Regards Mike