Manifolds can shed a fair bit of material before they become a problem.
Usually the risers go first. If both are the same age I would be more
worried about the risers.

Jumping out of gear is not common on alphas. The design is such that the
torque of the engine wants to force the lower unit further into engagement
rather than out. That's why they have a shift interrupt switch. If you
have ever had the switch go bad you know how hard it is to get an alpha out
of gear. I would check the cables before the drive. You can disconnect the
primary cable at the shift plate and then see how smoothly it operates
alone. There is also a short cable from the plate to the outdrive. There
have been a number of bulletins about the routing of the short cable. You
should also check for excessive slack in the cable With the long cable you
will always have some slack. The short cable should have little slack.
Wear in the housing will cause a cable to have a lot of slack.

Make sure that both cables operate freely and have the minimum number of
turns in the routing. As well as make sure that turns have as big a radius
as possible. Do not fix the long cable firmly to anything at the engine end
except the shift plate. It is the cable housing movement that activates the
shift interrupt switch. Make sure the shift plate lever is not twisting or
binding. When you reassemble follow the adjustment procedure in the manual.

There is no better check of the gimbal bearing than to pull the outdrive.
Once it's out you can reach in there and check it with your hand for play or
roughness when you try to spin it. Also check the u-joints as they can
become noisy too. With the outdrive off you can check the upper input for
play as well. The top plate on the upper half is also easy to remove and
will allow you to inspect that area as well.

"Tim" wrote in message
...
Well with temps starting to plummet, I thought I'd best put the babes
to bed. both m boats, I took them out of my warehouse, and ran them
home and hooked them up to the hose. Threw in a container of sta-bil,
ran the 3.0 up to operating tempfor about 15 minutes, then took it
down to the gas station and filled th tank., then took it back and
commensed to drain the water. no problem. winderizing a 3.0 is a snap.
very easy, but when I went to clean out the drain plug on the exhaust
manifold. I ran a nail up in there, and out came great flakes of rust!
lots of flaky rust. could this mean a new manifold is in my future?

Now on the 23' Marquis, same procedure. dump in sta-bil run for 15
min. fill tank. But while I was letting it run, I shifted the gears,
and this has a Morse type shifter. Big chrome device, long lever an
while shifting into forward or reverse, the gears caught but it seemed
like tey wernt fully engaged. and at about 1500 rpm, there was a deep
rattle coming from the lower end. Engine runs great and smooth (350 GM
Alpha 228) and I noticed that the throttle was a bit stiff, could this
be a cable needing adjusted or replaced?
The rumble, Gimbal bering going out? *ugh!*

With engine shut off and gears enguaged it all feels tight at the
prop, but when running and shifting it seems like there's some type of
gear noise. It's really hard for me to describe. Bow, I DID have it
slip out on me a couple times this summer when under a hard throttle.
fearing a runaway, I immediatly pulled back on the throttle,a nd the
gears caught. If I took it easy on acceleration, it would hold, but
when nailing it, it would kick out about 2600 rpm.

My chiltons manual doesn't say much on trouble shooting, so that's why
I'm asking. The boat is a 23' marquis cuddie, and I guestimate theres
at least 18 of throttle/shift cable considering the turns and bends.

What do you think?

Thanks!
Tim