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oceanis111 · 19-08-2013, 04:54

I am on a leak hunt in my Beneteau 311 (with Volvo MD2020).
I had the rubber shaft seal replaced about two years ago, which improved but did not completely fix things
During this year's lift out I sealed the shaft log with 3M4200, which reduced the leak considerably - and at least when she is dried out after a sail, she stays dry.
I have checked the hose nipple on the shaft log. It's Ok but I will change on next lift out.
But now, when the engine is running, especially at tickover with the shaft vibrating a bit, there is a noticeable leak, even a fine spray, from the shaft seal.
I have regularly greased the seal, and two years is a very short life span, but a question comes to mind. If the servicer used a 1" seal, rather than a 25mm, does anyone one if the difference would be enough to cause such a leak? Or does anyone have suggestions for the next step?
Thanks

goboatingnow · 19-08-2013, 05:02

why is the shaft vibrating, this could be the issue. either bad coupling alignment or bent shaft.

dave

MARINE ENGINNER · 19-08-2013, 05:06

Quote:

Originally Posted by oceanis111

I am on a leak hunt in my Beneteau 311 (with Volvo MD2020).
I had the rubber shaft seal replaced about two years ago, which improved but did not completely fix things
During this year's lift out I sealed the shaft log with 3M4200, which reduced the leak considerably - and at least when she is dried out after a sail, she stays dry.
I have checked the hose nipple on the shaft log. It's Ok but I will change on next lift out.
But now, when the engine is running, especially at tickover with the shaft vibrating a bit, there is a noticeable leak, even a fine spray, from the shaft seal.
I have regularly greased the seal, and two years is a very short life span, but a question comes to mind. If the servicer used a 1" seal, rather than a 25mm, does anyone one if the difference would be enough to cause such a leak? Or does anyone have suggestions for the next step?
Thanks

dear oceanis111 hello
the volvo seals can last 4-5 years but with an accurate engine-shaft alignment.if your shaft is aligned then check the surface area that the 2 lip seals touches if it is scratched.the second theory is not so common but might happen.

most common is misalignment of the shaft.then check your cutlass bearing if it is worn out of limits causing mialingment movement of shaft

oceanis111 · 19-08-2013, 05:59

Thanks for suggestions.
Can alignment check be done with boat in water?

oceanis111 · 19-08-2013, 06:08

Thanks for suggestions.
Is it possible to check the shaft alignment with the boat in the water?

**capngeo** · 19-08-2013, 06:10

Quote:

Originally Posted by oceanis111

Thanks for suggestions.
Can alignment check be done with boat in water?

Yes, remove the bolts at the coupler, use a feeler gauge to check between the faces; should be the same all the way around

**neilpride** · 19-08-2013, 06:15

Yes , its the best way, in the water, the boat hull in the water is free of distortions and get their normal shape.

Just be sure the shaft at the lip seal area is free of dings or pitting or some kind of defects , this is one of the main reasons for faulty seals and leaks ..