I've lurked a long time, and finally need to post and use the vast
experience here. I had my 85 Chris Craft Scorpion (200 HP Mercruiser
Alpha) out for the last time Friday before winterizing it.

We were towing the kids on the tube, and on the last go-round, the wife
shut off the boat to let a little one in, started it up, dropped it into
forward, and we had no thrust. Reverse was a no-go either. We tried
to go just barely above idle to limp us back. I immediately thought
spun prop. We had encountered deep mud about 3 weeks ago and were stuck
for a short spell in it. Nothing doing on limping, and one tow later we
were back on dry land. (Thanks to the two fishermen who helped out if
you read this)

Back on land with muffs on, we started it up. The wife moved the gear
lever forward, and the prop did turn at proper speed for the engine (it
appeared). After returning to neutral and trying again, the prop did
not spin. Same for several attempts in forward and reverse. I drained
the oil (have to winterize it anyways sometime) and took the lower unit
off. I did have the gear selector in forward for the removal.

With the lower unit off, I turned the lower driveshaft. No prop shaft
spin. I manually turned the gear lever to reverse and tried. No spin
either when appropriate turning applied. If I manually hold the shift
shaft in as far forward it can go in forward, I can sometimes get the
prop shaft to spin, but I feel a slight 'tug' backwards as if the shift
shaft doesn't want to stay in that position. Sometimes the prop shaft
will spin, other times it will 'catch' a few teeth, and sometimes not at
all. Mostly not at all.

Problems/observations that may or may not have exacerbated this situation:

1) Tendency to shift 'slowly' from neutral to a drive gear. (I know,
I've since learned this is a bad habit)
2) About 5-10 sec of good engine throttle with the prop not spinning in
the water. (First time we noticed the problem.)
3) Do not know last time any gear work was done. Engine of boat has
1200 hrs. Drive fluid changed yearly.
4) Fluid had no water and no chunks of metal.
5) Water pump impeller housing looked used, but not spectacularly worn.
6) Encounter with shallow mud about 3 weeks ago, which abruptly stopped
engine. Lower unit flushed and prop cleaned out of clay based hard
packed mud. No other visible external damage.
7) Boat operated total of 7 hours from mud until now.

Questions:

1) Is it possible (better if someone has actually seen the lower unit
pinion and forward/reverse gears to be the weak link/problem here? I
would have been sure the prop would give first, but not sure here...prop
splines and hub look good.

2) Will I need to haul the upper off and check for damage? The only
thing I've done so far is peek under the upper housing cover, and the
gears/bearings are intact and looking good.

3) The other thing that I question is the engine coupler. Since the
engine did spin at 1500-2000 RPM that 5-10 seconds the first time we
noticed the problem, I want to make sure I didn't hurt it. Also, if the
answer to removing the upper is yes, I'll be closer to it. Can you
check it without running the engine?

Thanks for your help. Sorry for the wordiness, but wanted to give the
group a clear description. I have plenty of follow up questions
regarding its repair, but let's start here. Thanks for your help.

Claus Fasting

It sounds like you have chewed the teeth off of the clutch or gear face.
Shifting slow will definately cause that. If the upper unit is clean (no
metal in the oil) then you should be able to just repair or replace the
lower. You can look at the top cover bearing for an indication if there was
metal flying around in there. If the bearing looks like it is worn evenly
then you should be okay.

The engine coupler should be fine, but it wouldn't hurt to pull the upper
off to inspect it as well as check the engine alignment and grease the
u-joints. You should be doing that yearly anyway.

Good luck,

Justin
"Claus" wrote in message
...
I've lurked a long time, and finally need to post and use the vast
experience here. I had my 85 Chris Craft Scorpion (200 HP Mercruiser
Alpha) out for the last time Friday before winterizing it.

We were towing the kids on the tube, and on the last go-round, the wife
shut off the boat to let a little one in, started it up, dropped it into
forward, and we had no thrust. Reverse was a no-go either. We tried to go
just barely above idle to limp us back. I immediately thought spun prop.
We had encountered deep mud about 3 weeks ago and were stuck for a short
spell in it. Nothing doing on limping, and one tow later we were back on
dry land. (Thanks to the two fishermen who helped out if you read this)

Back on land with muffs on, we started it up. The wife moved the gear
lever forward, and the prop did turn at proper speed for the engine (it
appeared). After returning to neutral and trying again, the prop did not
spin. Same for several attempts in forward and reverse. I drained the
oil (have to winterize it anyways sometime) and took the lower unit off.
I did have the gear selector in forward for the removal.

With the lower unit off, I turned the lower driveshaft. No prop shaft
spin. I manually turned the gear lever to reverse and tried. No spin
either when appropriate turning applied. If I manually hold the shift
shaft in as far forward it can go in forward, I can sometimes get the prop
shaft to spin, but I feel a slight 'tug' backwards as if the shift shaft
doesn't want to stay in that position. Sometimes the prop shaft will
spin, other times it will 'catch' a few teeth, and sometimes not at all.
Mostly not at all.

Problems/observations that may or may not have exacerbated this situation:

1) Tendency to shift 'slowly' from neutral to a drive gear. (I know, I've
since learned this is a bad habit)
2) About 5-10 sec of good engine throttle with the prop not spinning in
the water. (First time we noticed the problem.)
3) Do not know last time any gear work was done. Engine of boat has 1200
hrs. Drive fluid changed yearly.
4) Fluid had no water and no chunks of metal.
5) Water pump impeller housing looked used, but not spectacularly worn.
6) Encounter with shallow mud about 3 weeks ago, which abruptly stopped
engine. Lower unit flushed and prop cleaned out of clay based hard packed
mud. No other visible external damage.
7) Boat operated total of 7 hours from mud until now.

Questions:

1) Is it possible (better if someone has actually seen the lower unit
pinion and forward/reverse gears to be the weak link/problem here? I
would have been sure the prop would give first, but not sure here...prop
splines and hub look good.

2) Will I need to haul the upper off and check for damage? The only thing
I've done so far is peek under the upper housing cover, and the
gears/bearings are intact and looking good.

3) The other thing that I question is the engine coupler. Since the
engine did spin at 1500-2000 RPM that 5-10 seconds the first time we
noticed the problem, I want to make sure I didn't hurt it. Also, if the
answer to removing the upper is yes, I'll be closer to it. Can you check
it without running the engine?

Thanks for your help. Sorry for the wordiness, but wanted to give the
group a clear description. I have plenty of follow up questions regarding
its repair, but let's start here. Thanks for your help.

Claus Fasting

There is no clutches in the alpha. Shifting engages the main gears in the
lower unit.

It can be difficult to tell when the alphas are engaging when tunring the
shafts by hand. Alphas have a gear cut in the lower unit that holds them in
gear. Because of that when you spin the input shaft backwards this also
causes then to skip out of gear. You need to make sure you turn the imput
shaft on the lower unit the right direction when you are checking it.
Sometimes it helps to have someone apply a little "resistance" to the prop
shaft while you turn the input shaft and actuate the shift lever.

You can inspect the upper gears pretty easily just by removing the plate
from the top.

No metal in the oil means you should check the rubber coupling at the back
of the engine and the prop first. When a gear set goes there is usually
lots of metal fragments.

"Justin-SEI @sterndrive.cc" inforemove wrote in message
.. .
It sounds like you have chewed the teeth off of the clutch or gear face.
Shifting slow will definately cause that. If the upper unit is clean (no
metal in the oil) then you should be able to just repair or replace the
lower. You can look at the top cover bearing for an indication if there
was metal flying around in there. If the bearing looks like it is worn
evenly then you should be okay.

The engine coupler should be fine, but it wouldn't hurt to pull the upper
off to inspect it as well as check the engine alignment and grease the
u-joints. You should be doing that yearly anyway.

Good luck,

Justin
"Claus" wrote in message
...
I've lurked a long time, and finally need to post and use the vast
experience here. I had my 85 Chris Craft Scorpion (200 HP Mercruiser
Alpha) out for the last time Friday before winterizing it.

We were towing the kids on the tube, and on the last go-round, the wife
shut off the boat to let a little one in, started it up, dropped it into
forward, and we had no thrust. Reverse was a no-go either. We tried to
go just barely above idle to limp us back. I immediately thought spun
prop. We had encountered deep mud about 3 weeks ago and were stuck for a
short spell in it. Nothing doing on limping, and one tow later we were
back on dry land. (Thanks to the two fishermen who helped out if you
read this)

Back on land with muffs on, we started it up. The wife moved the gear
lever forward, and the prop did turn at proper speed for the engine (it
appeared). After returning to neutral and trying again, the prop did not
spin. Same for several attempts in forward and reverse. I drained the
oil (have to winterize it anyways sometime) and took the lower unit off.
I did have the gear selector in forward for the removal.

With the lower unit off, I turned the lower driveshaft. No prop shaft
spin. I manually turned the gear lever to reverse and tried. No spin
either when appropriate turning applied. If I manually hold the shift
shaft in as far forward it can go in forward, I can sometimes get the
prop shaft to spin, but I feel a slight 'tug' backwards as if the shift
shaft doesn't want to stay in that position. Sometimes the prop shaft
will spin, other times it will 'catch' a few teeth, and sometimes not at
all. Mostly not at all.

Problems/observations that may or may not have exacerbated this
situation:

1) Tendency to shift 'slowly' from neutral to a drive gear. (I know, I've
since learned this is a bad habit)
2) About 5-10 sec of good engine throttle with the prop not spinning in
the water. (First time we noticed the problem.)
3) Do not know last time any gear work was done. Engine of boat has 1200
hrs. Drive fluid changed yearly.
4) Fluid had no water and no chunks of metal.
5) Water pump impeller housing looked used, but not spectacularly worn.
6) Encounter with shallow mud about 3 weeks ago, which abruptly stopped
engine. Lower unit flushed and prop cleaned out of clay based hard
packed mud. No other visible external damage.
7) Boat operated total of 7 hours from mud until now.

Questions:

1) Is it possible (better if someone has actually seen the lower unit
pinion and forward/reverse gears to be the weak link/problem here? I
would have been sure the prop would give first, but not sure here...prop
splines and hub look good.

2) Will I need to haul the upper off and check for damage? The only
thing I've done so far is peek under the upper housing cover, and the
gears/bearings are intact and looking good.

3) The other thing that I question is the engine coupler. Since the
engine did spin at 1500-2000 RPM that 5-10 seconds the first time we
noticed the problem, I want to make sure I didn't hurt it. Also, if the
answer to removing the upper is yes, I'll be closer to it. Can you check
it without running the engine?

Thanks for your help. Sorry for the wordiness, but wanted to give the
group a clear description. I have plenty of follow up questions
regarding its repair, but let's start here. Thanks for your help.

Claus Fasting

James,

The forward and reverse gears are always being driven by the pinion gear in
the lower unit. If the engine is running all of the gears are turning. There
is a sliding clutch that engages either the forward or reverse gear to the
prop shaft depening on if you are in forward or reverse gear. In neutral the
sliding clutch sits in between the forward and reverse gear.

Justin

"James" wrote in message
nk.net...
There is no clutches in the alpha. Shifting engages the main gears in the
lower unit.

It can be difficult to tell when the alphas are engaging when tunring the
shafts by hand. Alphas have a gear cut in the lower unit that holds them
in gear. Because of that when you spin the input shaft backwards this
also causes then to skip out of gear. You need to make sure you turn the
imput shaft on the lower unit the right direction when you are checking
it. Sometimes it helps to have someone apply a little "resistance" to the
prop shaft while you turn the input shaft and actuate the shift lever.

You can inspect the upper gears pretty easily just by removing the plate
from the top.

No metal in the oil means you should check the rubber coupling at the back
of the engine and the prop first. When a gear set goes there is usually
lots of metal fragments.

"Justin-SEI @sterndrive.cc" inforemove wrote in message
.. .
It sounds like you have chewed the teeth off of the clutch or gear face.
Shifting slow will definately cause that. If the upper unit is clean (no
metal in the oil) then you should be able to just repair or replace the
lower. You can look at the top cover bearing for an indication if there
was metal flying around in there. If the bearing looks like it is worn
evenly then you should be okay.

The engine coupler should be fine, but it wouldn't hurt to pull the upper
off to inspect it as well as check the engine alignment and grease the
u-joints. You should be doing that yearly anyway.

Good luck,

Justin
"Claus" wrote in message
...
I've lurked a long time, and finally need to post and use the vast
experience here. I had my 85 Chris Craft Scorpion (200 HP Mercruiser
Alpha) out for the last time Friday before winterizing it.

We were towing the kids on the tube, and on the last go-round, the wife
shut off the boat to let a little one in, started it up, dropped it into
forward, and we had no thrust. Reverse was a no-go either. We tried to
go just barely above idle to limp us back. I immediately thought spun
prop. We had encountered deep mud about 3 weeks ago and were stuck for a
short spell in it. Nothing doing on limping, and one tow later we were
back on dry land. (Thanks to the two fishermen who helped out if you
read this)

Back on land with muffs on, we started it up. The wife moved the gear
lever forward, and the prop did turn at proper speed for the engine (it
appeared). After returning to neutral and trying again, the prop did
not spin. Same for several attempts in forward and reverse. I drained
the oil (have to winterize it anyways sometime) and took the lower unit
off. I did have the gear selector in forward for the removal.

With the lower unit off, I turned the lower driveshaft. No prop shaft
spin. I manually turned the gear lever to reverse and tried. No spin
either when appropriate turning applied. If I manually hold the shift
shaft in as far forward it can go in forward, I can sometimes get the
prop shaft to spin, but I feel a slight 'tug' backwards as if the shift
shaft doesn't want to stay in that position. Sometimes the prop shaft
will spin, other times it will 'catch' a few teeth, and sometimes not at
all. Mostly not at all.

Problems/observations that may or may not have exacerbated this
situation:

1) Tendency to shift 'slowly' from neutral to a drive gear. (I know,
I've since learned this is a bad habit)
2) About 5-10 sec of good engine throttle with the prop not spinning in
the water. (First time we noticed the problem.)
3) Do not know last time any gear work was done. Engine of boat has
1200 hrs. Drive fluid changed yearly.
4) Fluid had no water and no chunks of metal.
5) Water pump impeller housing looked used, but not spectacularly worn.
6) Encounter with shallow mud about 3 weeks ago, which abruptly stopped
engine. Lower unit flushed and prop cleaned out of clay based hard
packed mud. No other visible external damage.
7) Boat operated total of 7 hours from mud until now.

Questions:

1) Is it possible (better if someone has actually seen the lower unit
pinion and forward/reverse gears to be the weak link/problem here? I
would have been sure the prop would give first, but not sure here...prop
splines and hub look good.

2) Will I need to haul the upper off and check for damage? The only
thing I've done so far is peek under the upper housing cover, and the
gears/bearings are intact and looking good.

3) The other thing that I question is the engine coupler. Since the
engine did spin at 1500-2000 RPM that 5-10 seconds the first time we
noticed the problem, I want to make sure I didn't hurt it. Also, if the
answer to removing the upper is yes, I'll be closer to it. Can you
check it without running the engine?

Thanks for your help. Sorry for the wordiness, but wanted to give the
group a clear description. I have plenty of follow up questions
regarding its repair, but let's start here. Thanks for your help.

Claus Fasting

"Claus" wrote in message
...
I've lurked a long time, and finally need to post and use the vast
experience here. I had my 85 Chris Craft Scorpion (200 HP Mercruiser
Alpha) out for the last time Friday before winterizing it.

We were towing the kids on the tube, and on the last go-round, the wife
shut off the boat to let a little one in, started it up, dropped it into
forward, and we had no thrust. Reverse was a no-go either. We tried to go
just barely above idle to limp us back. I immediately thought spun prop.
We had encountered deep mud about 3 weeks ago and were stuck for a short
spell in it. Nothing doing on limping, and one tow later we were back on
dry land. (Thanks to the two fishermen who helped out if you read this)

Back on land with muffs on, we started it up. The wife moved the gear
lever forward, and the prop did turn at proper speed for the engine (it
appeared). After returning to neutral and trying again, the prop did not
spin. Same for several attempts in forward and reverse. I drained the
oil (have to winterize it anyways sometime) and took the lower unit off.
I did have the gear selector in forward for the removal.

With the lower unit off, I turned the lower driveshaft. No prop shaft
spin. I manually turned the gear lever to reverse and tried. No spin
either when appropriate turning applied. If I manually hold the shift
shaft in as far forward it can go in forward, I can sometimes get the prop
shaft to spin, but I feel a slight 'tug' backwards as if the shift shaft
doesn't want to stay in that position. Sometimes the prop shaft will
spin, other times it will 'catch' a few teeth, and sometimes not at all.
Mostly not at all.

Problems/observations that may or may not have exacerbated this situation:

1) Tendency to shift 'slowly' from neutral to a drive gear. (I know, I've
since learned this is a bad habit)
2) About 5-10 sec of good engine throttle with the prop not spinning in
the water. (First time we noticed the problem.)
3) Do not know last time any gear work was done. Engine of boat has 1200
hrs. Drive fluid changed yearly.
4) Fluid had no water and no chunks of metal.
5) Water pump impeller housing looked used, but not spectacularly worn.
6) Encounter with shallow mud about 3 weeks ago, which abruptly stopped
engine. Lower unit flushed and prop cleaned out of clay based hard packed
mud. No other visible external damage.
7) Boat operated total of 7 hours from mud until now.

Questions:

1) Is it possible (better if someone has actually seen the lower unit
pinion and forward/reverse gears to be the weak link/problem here? I
would have been sure the prop would give first, but not sure here...prop
splines and hub look good.

2) Will I need to haul the upper off and check for damage? The only thing
I've done so far is peek under the upper housing cover, and the
gears/bearings are intact and looking good.

3) The other thing that I question is the engine coupler. Since the
engine did spin at 1500-2000 RPM that 5-10 seconds the first time we
noticed the problem, I want to make sure I didn't hurt it. Also, if the
answer to removing the upper is yes, I'll be closer to it. Can you check
it without running the engine?

Thanks for your help. Sorry for the wordiness, but wanted to give the
group a clear description. I have plenty of follow up questions regarding
its repair, but let's start here. Thanks for your help.

Claus Fasting

A couple other things that haven't been mentioned yet. Since you have the
lower off and it doesn't seem to be going into gear when you move the shift
shaft into Forward, the shift crank could be bent or worn, or broken, or the
shift spool could be worn or the spring fatigued. With rounded cogs on the
gears and or sliding clutch, you might experience the drive popping into or
out of gear. I can't imagine anything wearing to the point of causing shift
failure without you noticing the shift quality gradually deteriorating.

Make sure you are turning the vertical drive shaft clockwise. Turn the shift
shaft clockwise to lock into forward gear. Alternatively you could turn the
propshaft counter clockwise as you shift into forward and watch for the
driveshaft to rotate.

There should be a maximum of 12 degrees play in the shift shaft while the
sliding clutch is held under tension by the forward gear. 6 degrees would be
ideal.

Another thing that could happen is that vertical shaft is made of two
different metels spun welded together. The shaft could have snapped at the
weld or at the very top where the o-ring goes.

I'd suggest you have a shop look at it. They could probably tell you what is
wrong without even taking it apart.

Good luck,
Jim

"Jim" wrote in message
ink.net...

"Claus" wrote in message
...
I've lurked a long time, and finally need to post and use the vast
experience here. I had my 85 Chris Craft Scorpion (200 HP Mercruiser
Alpha) out for the last time Friday before winterizing it.

We were towing the kids on the tube, and on the last go-round, the wife
shut off the boat to let a little one in, started it up, dropped it into
forward, and we had no thrust. Reverse was a no-go either. We tried to
go just barely above idle to limp us back. I immediately thought spun
prop. We had encountered deep mud about 3 weeks ago and were stuck for a
short spell in it. Nothing doing on limping, and one tow later we were
back on dry land. (Thanks to the two fishermen who helped out if you
read this)

Back on land with muffs on, we started it up. The wife moved the gear
lever forward, and the prop did turn at proper speed for the engine (it
appeared). After returning to neutral and trying again, the prop did not
spin. Same for several attempts in forward and reverse. I drained the
oil (have to winterize it anyways sometime) and took the lower unit off.
I did have the gear selector in forward for the removal.

With the lower unit off, I turned the lower driveshaft. No prop shaft
spin. I manually turned the gear lever to reverse and tried. No spin
either when appropriate turning applied. If I manually hold the shift
shaft in as far forward it can go in forward, I can sometimes get the
prop shaft to spin, but I feel a slight 'tug' backwards as if the shift
shaft doesn't want to stay in that position. Sometimes the prop shaft
will spin, other times it will 'catch' a few teeth, and sometimes not at
all. Mostly not at all.

Problems/observations that may or may not have exacerbated this
situation:

1) Tendency to shift 'slowly' from neutral to a drive gear. (I know, I've
since learned this is a bad habit)
2) About 5-10 sec of good engine throttle with the prop not spinning in
the water. (First time we noticed the problem.)
3) Do not know last time any gear work was done. Engine of boat has 1200
hrs. Drive fluid changed yearly.
4) Fluid had no water and no chunks of metal.
5) Water pump impeller housing looked used, but not spectacularly worn.
6) Encounter with shallow mud about 3 weeks ago, which abruptly stopped
engine. Lower unit flushed and prop cleaned out of clay based hard
packed mud. No other visible external damage.
7) Boat operated total of 7 hours from mud until now.

Questions:

1) Is it possible (better if someone has actually seen the lower unit
pinion and forward/reverse gears to be the weak link/problem here? I
would have been sure the prop would give first, but not sure here...prop
splines and hub look good.

2) Will I need to haul the upper off and check for damage? The only
thing I've done so far is peek under the upper housing cover, and the
gears/bearings are intact and looking good.

3) The other thing that I question is the engine coupler. Since the
engine did spin at 1500-2000 RPM that 5-10 seconds the first time we
noticed the problem, I want to make sure I didn't hurt it. Also, if the
answer to removing the upper is yes, I'll be closer to it. Can you check
it without running the engine?

Thanks for your help. Sorry for the wordiness, but wanted to give the
group a clear description. I have plenty of follow up questions
regarding its repair, but let's start here. Thanks for your help.

Claus Fasting

A couple other things that haven't been mentioned yet. Since you have the
lower off and it doesn't seem to be going into gear when you move the
shift shaft into Forward, the shift crank could be bent or worn, or
broken, or the shift spool could be worn or the spring fatigued. With
rounded cogs on the gears and or sliding clutch, you might experience the
drive popping into or out of gear. I can't imagine anything wearing to the
point of causing shift failure without you noticing the shift quality
gradually deteriorating.

Make sure you are turning the vertical drive shaft clockwise. Turn the
shift shaft clockwise to lock into forward gear. Alternatively you could
turn the propshaft counter clockwise as you shift into forward and watch
for the driveshaft to rotate.

There should be a maximum of 12 degrees play in the shift shaft while the
sliding clutch is held under tension by the forward gear. 6 degrees would
be ideal.

Another thing that could happen is that vertical shaft is made of two
different metels spun welded together. The shaft could have snapped at the
weld or at the very top where the o-ring goes.

I'd suggest you have a shop look at it. They could probably tell you what
is wrong without even taking it apart.

Good luck,
Jim

Check the lower shift cable as well. It can work in one direction even if
broken. The shift dog in the lower gear case will leave metal in the oil
most all the time, but lots if "gone".
Not as good a system as the Volvo clone "cone clutch" in the Bravo series.

Good luck! Dan