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Jim Jim is offline
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First recorded activity by BoatBanter: Jul 2006
Posts: 338
Default Mercruiser A-1 gear lube consumption

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.

"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