Input shaft lip seal leaking....calling on your experience??

[Matata]

Sort of boaty...we have an outboard where the output shaft from the engine goes down to the gearbox which sits in the water and has the prop on it. We found traces of sea water in the gear box oil so decided to change the lip seals on/in the gear box. Mr .Yamaha said it was difficult to get a new seal to seal correctly as the input shaft from the power head was slightly scored as it entered the gearbox and hence letting water past the seal. IN PRINCIPLE is it possible to have the shaft slightly reground, and say take off 10 thou, to put a new face on it so the lip seal would work? Any suggestions or advice would be really appreciated....yours Nik

 

[Balbas]

In my (limited) experience, 4 things are likely to cause leaks from lip seals:-

1) longitudinal scratches which will allow leakage past the seal
2) burrs, snags and sharp edges on the shaft which will chew the lips up in double quick time
3) bent shaft
4) cheap, non original lip seals.

I wouldn't regrind the shaft unless it was really bad, but noting points 1) and 2) above, I would take some emery tape and *working around the shaft rather than up and down the shaft* polish any scratches out.

In the application you describe you're unlikely to experience 3) and 4) is easy to avoid.

 

[captainboo]

Can you fit one of these:-

https://www.skf.com/uk/products/sea...als/wear-sleeves/skf-speedi-sleeve/index.html

Have used on my PRM gearbox to good effect.

 

[vyv_cox]

The dodge highlighted by captainboo is a good option. An even easier one that works in some instances is to shim the seal out in its housing so that the lips run on an unworn part of the shaft.

 

[Matata]

Brilliant....Thanks guys. I need over the next few weeks work out how severe this water leak is and it may well be my winter project. Nik