You can run the engine without the outdrive. You can just hook a garden
hose onto the water line coming in from the outdrive and run water through
it. You just need a piece of plastic tubing to clamp the hoses to. I've
run mine that way. When you've got the outdrive on put some muffs on it.
If you don't have any muffs buy some, they are only about $15 and you need
them anyway. Even with a bad impeller you can usually get enough water
through the muffs from the garden hose pressure to keep it cool running in
the driveway. As others have pointed out the rubber exhaust components will
get hot pretty quickly and they will melt. They were not made for straight
exhaust, they were made for wet exhaust. And the lower unit water pump is
IN the exhaust stream going out the prop. It is plastic too. Just no
reason to not give it water since all you need is a garden hose.

If you have burned up the coupler you should be able to see evidence of
that. Melted rubber, etc around the outside. It won't strip the splines,
the rubber will spin inside the housing. If it has spun at all then it is
shot. You're trying to transfer a couple hundred hp through the thing. I'm
guessing you burned up some exhaust rubber or the water pump impeller. Or
maybe the oil from when it was winterized last. Get some water in the thing
so you can run it for awhile then you can troubleshoot.

It is not odd for mercs to not be a 'perfect' fit even after being aligned.
Anyone doubts me just get yours perfect and then turn the engine 1/2 turn
and you'll see what I mean. Merc couplers have no center alignment bushing
so they are never perfectly centered on the flywheel anyway. Slightly out
of alignment is not going to bother the u-joints or make them 'catch'. They
take far bigger stresses on turns and trimming.

"JIMinFL" wrote in message
link.net...
The water pickup is in the upper gearcase exhaust path and holds the
copper pickup tube that fits into the top of the water pump, by means of
an interfereance fit rubber bushing. The exhaust shutter is a stainless
steel plate with a rubber edge which helps it seal better. Those are at
the top of the Y pipe and directly in the path of escaping exhaust gasses.
You can tell when they have either melted or are worn out by the annoying
rapping noise they make. The noise is so alarming that you would think
your engine is self destructing. Those rubber hoses I spoke of contain the
exhaust gasses from escaping into the engine room and causeing a fire. I
will guarentee you that if you can't hold your hand on one of those hoses
for at least several seconds, the hose is charring and will eventually
rupture.

You may not have damaged anything, but the previous owner might have. I
think you said this boat is new to you.
Now that you have it all apart, you might as well inspect everything that
you can. Can you run the engine on a stand to make sure the engine isn't
making the noises? I understand the exhaust noise will make it hard to
hear anything else but maybe you could poke around with a stethascope and
listen to the various engine noises.

Do some troubleshooting and report back what you find.

JIMinFL



"Proxy" wrote in message
...
Appreciate the info on the coupler.
As to the dry run seems that you are ech oing same thing that I've
already heard. Let me repeat then, no engine or major engine part will
get hot within the time intervals that I'm talking about. Not even
exhaust. Exhaust shutters are made for high temp, and plastic water
pickup does not expel exhaust gasses, "those rubber hoses" you refer to
are made for exhaust, let's not forget, and under normal operating
conditions withstand very high temp.
As I said before, no need to cool if something is still barely warm. Try
it or you will never know. Nothing personal.




"JIMinFL" wrote in message
ink.net...
You have gotten a lot of good information so far. Here's some more.

Water is needed, not only to keep the engine cool, but also cools power
steering fluid, and those rubber hoses between the exhaust riser and
wishbone. The exhaust shutters, and plastic water pickup fitting in the
upper gearcase are also in the path of hot exhaust gasses. Also, the
engine should not be started with the sterndrive in the tilted position.
You risk tearing the u-joint bellow, damaging the gimbal bearing,
u-joints, and possibly the engine coupler. The u-joints, at the very
least will make a very unhappy noise if run at extreme angles.

Look carefully at the coupler splines and the splines on the sterndrive
yoke. If you had an allignment problem, you should see evidence on the
splines. To test for coupling, you will need an old yoke with the
u-joint removed. Hold the coupler in a fixture or mount it on the
engine. Put the yoke in the coupler and a 2' pipe thru the u-joint
socket. The coupler should be able to take at least 200lb torque without
slipping. One other test you might do is to check for runout. I'll let
you figure out how to do that.

You should take the top cover off the sterndrive and make sure
everything looks happy inside.
You should drain all the gear oil and make sure you don't see metal
filings or water.
You should install a new water pump body kit after finding and removing
all broken impeller pieces.
You should make sure the upper gear housing moves freely while feeling
for a bad bearing.Same goes for lower gearcase,except you need
to check for proper shifting.
You should check for propshaft runout.

I'm sure I left out a lot of details and would hope you have the proper
OEM service manuals to guide you.

Hope some of this information is helpful.

Good Luck
JIMinFL


"Proxy" wrote in message
news Thanks. At this stage I'm not even thinking about rattling/clunking
noise. When I put the engine together I'll have one more chance to
reexamine everything. I have the engine hanging on chains and wonder
how do I go about the coupler. The rest will come later. One thing I
know 4 sure that 2 mechanics have missed the alignment part (or thought
that it may be ignored for a while and both were wrong). Most upsetting
is that I pointed that out to both and from that moment became an
annoyance. They seemed to have no appreciation for other point of view
at the moment.

Now, I've had a look at the coupler and seen zero damage but.since the
idea of the coupler is to inject a weak point into the drive system to
protect crank and drive shafts I wonder where is the breaking point for
a coupler. If a spun coupler (for a few secs) may still be usable or
regardless of its look should be replaced anyway. With other words, is
this enough to spin it just one turn to break the rubber layers bond or
does it remain good until the spinning visually separates rubber
bushings (burned, melted rubber would be visible then). Since the
engine is stripped of exhaust I have to work backwards, start with the
coupler, put the exhaust, linkage, electrical together and test
yoke/u-joint play, engine alignment and potentially outdrive issues.
Just don't want to put it back together to later have to dismantle it
again to yank the coupler out. I don't feel like going back and forth
few times over.

As indicated impeller is just a cost of testing which I don't mind.
Otherwise I see no issues with running the engine dry as long as there
is sufficient lubrication. As I said I've done it several times on
different engines always successfully without any issues or signs of
trouble (no need for cooling something that is still cold). But that
issue is beyond the scope of this subject. Coupler is.
Btw. Cobra has the best setup allowing impeller removal in just few
minutes. Very handy, at least in my opinion.

My take is this: the engine was out of alignment which has caused
u-joint jamming momentarily and that has caused coupler to let go for a
moment (blue smoke from the engine compartment - back of the engine -
typical for coupler failure) and was immediately shut down.


"Mr Wizzard" wrote in message
...

"Proxy" wrote in message
...

damage except for impeller that I have written off anyway for this
experiment.

Ah, Ok, I didn't realize that you wrote off the impeller (I missed
that)
(but the rubber smell could be the impeller galling up down there)

So, you didn't say anything about the U-joints. And when
mechanic dude said the yoke "isn't right", whats that mean?
Wrong one, wrong size, or bad, or what?

have you peaked inside the outdrive? bled a little bit of
grear juice out the bottom of the lower unit to look for
shavings? You replaced the coupler, or said that there
is no visable damage, or difference between that one,
and the one that was given to you, so I can't see that
being the problem. Besides, think about it, there is
nothing really to rattle there - the spline is a very percision
fit, and nothing really to rattle. Things that can rattle a
connecting rods, pistons, U-joints, yokes, bevel gears etc.
Could they have missed the shift-shaft lever alignment when
putting the outdive on? - dog clutch caught between gears?
Its all a pretty solid chunk of metal down there, so noise
can be transmitting from anywhere.

Hate to be stupid here, but are you SURE its not the motor?
i.e. since your not worried about water, cooling, impellers,
can you pop the outdrive off, and try to run the motor wihtout
the outdrive ? And whats the gimbal bearing look like ?
The front input shaft bearing for the outdive unit itself ?

Keep us posted.