"Jim" wrote in message
ink.net...
The bushing assembly( used to be metal) has a groove the oring fits into.
It
would be pretty difficult to unseat this oring. The oring seals the
bushing
assembly to the gear housing. in the middle of the bushing are pressed 1
or
2 seals (I forget). The shift shaft is sealed by these seals. the shift
shaft rotates about 45 degrees. The shift shaft is in front of the water
pump and in back of the cavity I spoke of. There is only 1 drain hole for
the cavity. There is no pressure relief issue since the gear lube is able
to
expand and contract and fill and empty the reservoir just like the
expansion
tank for your car cooling system.

Cool - yeah, I was reading about the shaft positions - 10:00 Rev,
11:00 neutral, and 12:00 forward. Ok, cool, so the bushing itself
has little seals preseed in seals. Geeze, with only an occassional
45 degrees movement, don't see why it would be so common for
the shift shaft seals to leak. Maybe thats just it - the shaft never
moves 360 degrees, so maybe it never gets proper wiping and
seating on seal lip or somehting? who knows. Also, on mine,
(2005 Alpha-1 Gen II), there really are 2 drain holes, one on
each side of the lower unit towards the rear. And so yeah, I
agree about the venting (up into the gear lube monitor) so I don't
know why the Olympic boat center service department dude
told me on the phone that the shift shaft seal also acts as a
pressure relief. Also read where some people say there is a check
valve in line with the tank and the drive, and other say no. But
there really -can't- be a check valve since the refill procedure
says to pump the gear lube "up" from the lower unit until it
fills the gear lube monitor - somehting you wouldn't be able to
do if there were a chack valve in line. Anyways... So what is
your experience with the newer Alpha-1's (gen 2) drives ?
How likely is it that my shift shaft seal is what is leaking?
How involved is dropping the lower unit to have a peek?
Or should I say, how involved is re-assembling it correctly?
I assume that you can do this with the outdrive on the boat?
Probably just wait for y service appointment in 2 weeks,
but just curious (roll-away chock full of tools on a cloudly
Saturday, and its killing me that I can't dive in). Course, no
"special" Mercruiser tools in the tool boxes anyhow. Got all
the Ford 4x4 differential tools, - do they count? (Ok, joking)






"Mr Wizzard" wrote in message
...
Yup - also think I'm getting the picture here too...
Correct me if my thinking is off here. Shift-shaft
is on the starboard side, and water pump on port.
Since port side is bone dry, and s.b. side a tad wet,
I suspect shift-shaft bushing seal. Also, (finally)
understand the shift shaft bushing thing now. So
I been seeing pics of the ss "bushing", and tools
to screw in/out the bushing, but failed to under-
stand how a hard plastic collar bushing could be
a seal. Finally found a web page that explains it.
Its a hard plastic threaded bushing with slots on
the top (to screw it in/out), BUT, its got n O-ring
down inside of it. Somewhat common for the O-
ring to pop out, or walk itself out of hte center of
the bushing, and just float around the shaft on the
top of the bushing. So..... Got an appointment
for Aug 16th (2-weeks from now), so we'll go
from there. Question is, is it bad enough to have
to stop using it for the next 2 weeks - thats what
I have to evaluate now. Fear being getting water
in the drive. Also, had another dealer tell me on
the phone that the shift-shaft seal also acts as a
pressure relief valve. (?) Don't understand that
as all! - if so, pressure would pop the O-ring out
of the hard plastic shift-shaft bushing, but that
action would be permanent, right? How could
an O-ring act as pressure relief and remain in tact?
(guess I'd just have to see it all apart on the bench)




Jim