Re: [OMC-Boats] Upper Unit Seal questions

On Wed, 10 Jun 2009, BLDFW wrote:
>Using the correct parts manual, I'm compiling a seals and o-ring listing
>so I can properly reseal my upper unit. Fortunately all of
>the "seals and o-rings" are still available individually through
>MarineEngine.com so I'm about to place the order

I'd be interested in seeing your list when you get all done - I noticed
some water in my upper unit oil last time I winterized and I'm planning on
tearing it apart this winter to replace whatever seal has gone bad. A list
of parts and vendors would certain help this process.

> PN 308768 Exhaust Seal
> PN 308590 Spring  (related to the previous part)
> They appear to seal the exhaust outlet in the upper unit where it mates
> with the port on the intermediate housing.  I don't see anything that
> resembles these them on my upper unit (see pic).   Is this a part that
> gets lost?  The inside of the upper unit cavity around the port is all
> black so it's not been there for awhile

The "exhaust seal" is this large black rubber ring gasket that fits in the
outdrive, where it seals up against the intermediate housing. The gasket
slips onto the outdrive side and seals around the outer edge. I'm not
quite sure what the spring is, but perhaps it fits around the gasket and
pinches it in place? I've always thought it looked prone to falling off,
especially when trailering with the drive raised. I never thought about
whether there might be a spring to hold it in place - perhaps that's why I
haven't lost mine. I thought the gasket was visibly "split" (i.e. a gap in
one location) though, which would correspond to not having a spring. but
perhaps I'm mis-remembering. I just looked at the parts list though:

at epc.brp.com
sterndrive
1970
155
HUFM-19E-1970

and 308768 is the "Exhast seal" and 308590 is the "Spring, seal" and
they're part 26 and 27, which correspond to what I remember. So it's
probably a two-piece gasket with a retaining spring... Ahh, it looks like
it's a rubber gasket with a split spring stretched over it - the spring is
probably a bent ring of spring steel that pinches the gasket into place,
rather than the long tension spring loop I was expecting.

Here's a picture from when I had my outdrive separated:
  http://homepages.cae.wisc.edu/~brodskye/boat/parts/out_upper.jpg
The seals is around the perimeter of the circular port in the front center
of the drive (with the vertical division going down the middle).

> Also, one other question.  PN 308596 Seal, is the big round plastic seal
> that the water pump housing slips through when placed in position inside
> the exhaust housing.  It's a $38.00 part.  Mine is present and in good
> condition.  I'm not seeing any reason to replace it.  Anyone got an
> opinion on that?

308596 is the "seal, exhuast housing", which I remember being a huge gasket
that fits between the upper and lower unit (#38) - the drive rotates on it.
Mine was pretty ratty, but I forgot to order a new one, and haven't had any
issues there yet after five years. The upper and lower gear casings are
sealed separately, so I think the only consequence of having a bad seal
there would be leakage of exhaust out of the drive around the perimeter,
which shouldn't be a big deal. I wouldn't worry about it, especially if
yours looks good.

Ethan

-- 
<a href="http://www.engr.wisc.edu/~brodskye/"> Ethan Brodsky </a>