Changed my impeller today, and when removing the lower unit, I noticed
that I had a slight oil leak from the upper shift shaft that was running
down the shift shaft to where the lower and upper shift shafts come
together. And then unceremonially dripping to the floor.

Can someone tell me if there is supposed to be oil anywhere near the
upper shift shaft? I know it shouldn't be leaking but I'm concerned that
it points to a bigger problem like oil in the exhaust bellow? I'm having
a hard time visualizing where outdrive oil bathes the upper shift shaft
to allow for this type of leak. Anyone with insight of the oil cavities
inside of a mercruiser pre-alpha drive?

chris wrote:
Changed my impeller today, and when removing the lower unit, I noticed
that I had a slight oil leak from the upper shift shaft that was running
down the shift shaft to where the lower and upper shift shafts come
together. And then unceremonially dripping to the floor.

Can someone tell me if there is supposed to be oil anywhere near the
upper shift shaft? I know it shouldn't be leaking but I'm concerned that
it points to a bigger problem like oil in the exhaust bellow? I'm having
a hard time visualizing where outdrive oil bathes the upper shift shaft
to allow for this type of leak. Anyone with insight of the oil cavities
inside of a mercruiser pre-alpha drive?

I can't visualize it either.
There are two seals on the vertical drive shaft in the upper unit that
could be leaking. There is a shift shaft seal in the lower unit. There
are 2 seals in the water pump base. If the bellows leak oil you have 2
problems. The bellows itself and the yoke seal.

Update:
Ran her yesterday for a few hours in the lake. Brought her home for the
night. Checked this morning, and the seal/shaft isn't leaking anymore.
Crazy.

Only thing I can think of:

I never saw the leak until I removed the lower unit to replace the
impeller. I replaced the impeller b/c temp rose to 180 on earmuffs while
flushing and running in a new manifold gasket + riser. Usually it runs
at 140. In other words, everything in back of the manifold got hotter
than it's ever been run, maybe introducing gunk into the exhaust path
and melting any lube on the shift shaft .

Also, to take off the lower unit, after stopping the motor I trimmed the
outdrive up- to the point where possibly the upper shift shaft lower
seal (in the bell housing) represented a small 'dip' in the exhaust
path- so that any water and associated crap still in the exhaust all
gathered in the bell housing right at the shift shaft, and chose to leak
down the shaft and out of the bellhousing.

No one I've talked to can figure out how any gear lube or engine oil
could possibly leak from anywhere near the upper shift shaft in the bell
housing, and that as long as outdrive and engine oil look full and clean
of water, I'm good to go. If anyone can think of how any type of lube,
oil, or even water could leak out of the upper shift shaft/bell housing,
I'd appreciate it.




jiminfl wrote:
chris wrote:

Changed my impeller today, and when removing the lower unit, I noticed
that I had a slight oil leak from the upper shift shaft that was running
down the shift shaft to where the lower and upper shift shafts come
together. And then unceremonially dripping to the floor.

Can someone tell me if there is supposed to be oil anywhere near the
upper shift shaft? I know it shouldn't be leaking but I'm concerned that
it points to a bigger problem like oil in the exhaust bellow? I'm having
a hard time visualizing where outdrive oil bathes the upper shift shaft
to allow for this type of leak. Anyone with insight of the oil cavities
inside of a mercruiser pre-alpha drive?


I can't visualize it either.
There are two seals on the vertical drive shaft in the upper unit that
could be leaking. There is a shift shaft seal in the lower unit. There
are 2 seals in the water pump base. If the bellows leak oil you have 2
problems. The bellows itself and the yoke seal.