"Proxy" wrote in message
...
Hi,
I've been recently offered a used coupler as I suspected mine to be shot.
I
lifted my 4.3 Merc and removed the old one. Both "new"-used one as well as
the old one looked exactly the same. I inspected the rubber, splines were
no
different and looked exactly identical to the smallest detail.

Since the suspected damage was due to the engine misalignment

So how did the engine get misaligned? or is this "suspected"
misalignment ? As I see it, the only way misalignment could
happen is the bushing in front tripod mount got beat out, or
someone messed with the adjustment, or something in the
transom mount, or the transom (or the entire structure) got
shifted, or racked ot something.


(lots of rattling and
clunking in the back of the engine (sounded like a piston rod broke loose
and was hitting cylinder walls)

Sounds more like U-joints, or outdrive related. Did you check that ?
Also, check it with the cups on (in neutral) - should be able to walk
about the back and check it more closely. Since the U joints run at
the same speed at the engine (and connecting rods), that could be
your noise. (are you sure its *not* a connecting rod) ?

Is this an Alpha One drive? (or an older OMC etc ?)


and I ran the engine dry for about 3x 10-15 sec.

How ? 15 seconds, and *three* times?? I'd revisit
your boat operating procedures, because thats hard
to do, and quite frankly, on and a stern drive, thats
borderline operator abuse. (15 Sec is a LONG time).



(last occurrence with some (not much) blue smoke from behind the
engine, immediately shut down)

Blue smoke? god gawd!. What did the smoke smell like?
Oil, or other? (rubber, etc)

I wondered how severe the damage could be
with respect to the coupler condition..

So why do you suspect the coupler? Moreover,
why do you suspect misalignment? What is the
history of this rig ?

Visually there is no way to tell the
difference between the two. Is there any other way to determine how was my
coupler affected, could it be still OK?.

Again, I think you need to tell us more about the history
of this situation. Why do you suspect misalignment?
You should have pulled the outdrive and checked
alignment with an alignment tool before pulling the motor.
Was there ample greese in the splines?

What would constitute a definitive
damage to the coupler? Simplest would probably be to drop the boat on the
water but this is out of the question at the moment (engine is still
disconnected). Any suggestions?

Your questions seem strange - why would you go
and pull the motor like this without checking into some
of the basics (like engine alignment) ??