Mercruiser i/o will not go into neutral
 

Hi,
I have a 1999 Bayliner capri with a 4 cylinder mercruiser. When the
boat is out of the water and connected to the water hose and running.
It shifts in and out of gear fine. When the boat is in the water and I
switch the gear shift to neutral, it will NOT go into neutral most of
the time...it just stays at the "no wake" speed but the shifter is in
neutral. I have to shift it back and forth to get it to finally go to
neutral. Any help would be greatly appreciated.

Scott

Mercruiser i/o will not go into neutral
 

Mercruiser i/o will not go into neutral
 

wrote in message
oups.com...
Hi,
I have a 1999 Bayliner capri with a 4 cylinder mercruiser. When the
boat is out of the water and connected to the water hose and running.
It shifts in and out of gear fine. When the boat is in the water and I
switch the gear shift to neutral, it will NOT go into neutral most of
the time...it just stays at the "no wake" speed but the shifter is in
neutral. I have to shift it back and forth to get it to finally go to
neutral. Any help would be greatly appreciated.

Scott
Probably the shifter cable is bad, your shifter kill switch is not engaging.
This shows up with DOG type gears. The engine has to be moving slower than
the prop for the gear to go into neutral thus the kill switch. (In the water
because of the inertia of the water the prop is always going to be running
slower than the engine unless the kill switch is working.)

Mercruiser i/o will not go into neutral
 

The shift interrupt should Not cut out the ignition if the cable is in
good working order AND adjusted correctly. The purpose of the interrupt
switch is to prevent damage to the drive from the throttle opening
before forward or reverse gear is engaged. A number of models did not
come supplied with interrupters at all. I would check the adjustment,
if incorrect, adjust to spec, if still sticking then check the lower
shif cable. You can sometimes see dried mineral deposits directly under
the engine end of the lower cable, indicating a leaky shift bellows and
probable damage to the cable, it only takes a few ounces of extra
resistance to cause a problem, but if you do have a shift interrupt
switch ,the engine will stall when shifting(as it should to prevent
damage.)..Also make sure your idle speed is correct...
markvictor

Mercruiser i/o will not go into neutral
 

The shift bellow doesn't seal water out of the cable. If the bellow leaks
the boat will take on water. A defective shift shaft bushing is the main
cause for water intrusion into the shift cable. An inoperable interrupter
may be causing difficulty pulling out of gear and inadvertantly shifting
into the opposite gear. Idle speed too high will cause this as well but the
shift clunk will be unusually loud. If the throttle opens too soon, your
cables need adjusting. If the engine stalls while shifting there is
excessive resistance in the lower cable or linkages.
Jim

"markvictor" wrote in message
oups.com...
The shift interrupt should Not cut out the ignition if the cable is in
good working order AND adjusted correctly. The purpose of the interrupt
switch is to prevent damage to the drive from the throttle opening
before forward or reverse gear is engaged. A number of models did not
come supplied with interrupters at all. I would check the adjustment,
if incorrect, adjust to spec, if still sticking then check the lower
shif cable. You can sometimes see dried mineral deposits directly under
the engine end of the lower cable, indicating a leaky shift bellows and
probable damage to the cable, it only takes a few ounces of extra
resistance to cause a problem, but if you do have a shift interrupt
switch ,the engine will stall when shifting(as it should to prevent
damage.)..Also make sure your idle speed is correct...
markvictor

Mercruiser i/o will not go into neutral
 

"markvictor" wrote in message
oups.com...
The shift interrupt should Not cut out the ignition if the cable is in
good working order AND adjusted correctly. The purpose of the interrupt
switch is to prevent damage to the drive from the throttle opening
before forward or reverse gear is engaged. A number of models did not
come supplied with interrupters at all. I would check the adjustment,
if incorrect, adjust to spec, if still sticking then check the lower
shif cable. You can sometimes see dried mineral deposits directly under
the engine end of the lower cable, indicating a leaky shift bellows and
probable damage to the cable, it only takes a few ounces of extra
resistance to cause a problem, but if you do have a shift interrupt
switch ,the engine will stall when shifting(as it should to prevent
damage.)..Also make sure your idle speed is correct...
markvictor


All correct except the shift engine kill switch SHOULD engage if there is
any resistance disengaging from reverse or forward into neutral. This
resistance (if shift cable is good) comes from the dog gear not disengaging
because the engine is running faster than the prop. The kill switch engages
and the motor slows relative to the prop and the gear can disengage.

Mercruiser i/o will not go into neutral
 

markvictor wrote:

The shift interrupt should Not cut out the ignition

Yes, it should... not entirely, just enough to shake the clutch dog off
the gear.

if the cable is in
good working order AND adjusted correctly. The purpose of the interrupt
switch is to prevent damage to the drive from the throttle opening
before forward or reverse gear is engaged.

Different adjustment.

A number of models did not
come supplied with interrupters at all.

Alphas?

I would check the adjustment,
if incorrect, adjust to spec, if still sticking then check the lower
shif cable.

The most likely problem.

Rob

Mercruiser i/o will not go into neutral
 

Jeff Rigby wrote:

All correct except the shift engine kill switch SHOULD engage if there is
any resistance disengaging from reverse or forward into neutral.

I agree, but when the control cable and lower shift cable are in good
condition, and adjusted correctly, the only way the clutch is "loaded",
is essentially when underway above nominal idle,or excessive rpms prior
to shifting, thus keeping tension on the clutch dogs.



if the cables are out of adjustment, When trying to engage
from neutral, if the rpm's are too high from premature throttle
opening,the clutch will resist and the interrupt switch is actuated.
When in gear,if the throttle is not closed and rhe RPM's are ,once
again, higher than nominal idle speed, the clutch dogs resist
disengagement, again tripping the interrupt switch...



This resistance (if shift cable is good) comes from the dog gear not disengaging
because the engine is running faster than the prop. The kill switch engages
and the motor slows relative to the prop and the gear can disengage.


If the engine is running, and the drive is engaged (in gear) It is
absolutely impossible for the engine to EVER run slower than the
propshaft...Alpha ratios (1.50 1.62, 1.81, 2.00, etc..) are all greater
than 1. This means that with a 1.50 to 1 gear ratio, the engine is
turning one and a half turns for every one turn of the propshaft...so
at 1500 tach rpm, the shaft is turning 1000rpm...at 3000 tach rpm, the
propshaft turns at 2000 rpm...at 600 tach rpm the shaft turns at 400
rpm,...at 150 tach rpm, the shaft would turn at 100 rpm aand so on,till
the engine is at a dead stop. A momentary spark interruption does not
stop the engine. If you try to do full throttle direction changes, the
interrupter should move to prevent damage, but in normal operation, the
throttle hits the stop before the shift action proceeds, and the
decelleration of the motor unloads the clutch dogs, and if the boat is
moving, the flow of water over the prop actually aids in unloading
it....Bottom line, the two causes of interrupter activation is
attempting high load shifts, either from too rapid shifting at high rpm
or misadjusted cables, or a simulated shift load caused by resistance
from a damaged cable or possibly a heavily worn selector shaft bushing
and seal.

wrote:
When the boat is in the water and I
switch the gear shift to neutral, it will NOT go into neutral most of
the time...it just stays at the "no wake" speed but the shifter is in
neutral. I have to shift it back and forth to get it to finally go to
neutral. Any help would be greatly appreciated.

The fact that the control handle is in the neutral position but the
clutch is still engaged, is a pretty clear indication that there is not
enough throw on the lower cable. This is often caused by the cable end
on the interrupter bracket being positioned incorrectly in the slot on
the cantilever.. On the v8's and v6's it should be at the bottom of the
slot, but if memory serves me correctly, the 4 cyl. plate is inverted
and the cable should be at the top of the slot. That will increase
throw on the lower cable, and minimize or eliminate any unnecessary
movement of the switch. If it was a bad cable, or high rpms, it would
stall the motor while hunting back and forth to find neutral

trainfan1 wrote:

Yes, it should... not entirely, just enough to shake the clutch dog off
the gear

No, it shouldn't, unless something is wrong...or you're shifting
improperly, such as lock to lock..

Different adjustment.

Of course it is, it's the throttle cable, but that can cause premature
opening of the throttle plate, which in turn causes rpms to increase
prior to gear engagement,which causes increased effort tho engage the
clutch dogs,which should cause the interrupter. to actuate, which
causes the boat to stall, etc etc,...But that's what's supposed to
happen if the throttle opens too soon....

Jeff Rigby wrote:
Probably the shifter cable is bad, your shifter kill switch is not engaging.

That is when it would engage, if the cable was bad

The engine has to be moving slower than
the prop for the gear to go into neutral thus the kill switch. (In the water
because of the inertia of the water the prop is always going to be running
slower than the engine unless the kill switch is working.)

I repeat, as long as the drive gear is engaged the engine will turn
faster than the propshaft,
it's a positive engagement clutch, ans a fixed ratio...there can be no
change of one without the same proportional change of the other until
AFTER disengagement occurs, not before...

JIMinFL wrote:
The shift bellow doesn't seal water out of the cable. If the bellow leaks
the boat will take on water. A defective shift shaft bushing is the main
cause for water intrusion into the shift cable

You're absolutely right,,,

Mercruiser i/o will not go into neutral
 

markvictor wrote:
Jeff Rigby wrote:


All correct except the shift engine kill switch SHOULD engage if there is
any resistance disengaging from reverse or forward into neutral.


I agree, but when the control cable and lower shift cable are in good
condition, and adjusted correctly, the only way the clutch is "loaded",
is essentially when underway above nominal idle,or excessive rpms prior
to shifting, thus keeping tension on the clutch dogs.

markvictor, you're confusing yourself immensley.

Brand new Alpha. Disconnect the interrupter. Guess what? It wont come
out of gear, even at idle(in water, under way), unless you use the cable
and pull the shift lever past neutral into reverse... then guess what?
you're in reverse! From neutral, it'll go INTO gear all day long no
matter how fast you shift & throttle(& actually, the faster you shift
the better for the dog & gears in the foot - none of that
chunka-chunka-chunka-chunka-clunk stuff...).

Makes docking tough.

Connect the interrupter. Shifts like a dream(at least as good as a dog
clutch leg can)!

Rob

Mercruiser i/o will not go into neutral
 

My understanding of the purpose of the interrupter is that because of the
design of the clutch dogs on the sliding clutch ( back cut 2 or 3 degrees or
somesuch), it is necessary to release the torque applied to the clutch to
make it easier to disengage same. To prove the point, disconnect one of the
wires on the interrupter microswitch and notice how much more difficult it
is to disengage gears while the engine is running. Also notice that there is
a tendency to overshift into the opposite gear.

Older Mercruisers didn't have the back cut clutch dogs and had a tendency to
fall out of gear at idle speed as the dogs became rounded from wear.

Earlier I made mention of a shift shaft seal. What I was referring to would
be more correctly called a bell housing bushing seal.

The original poster didn't say if he was having difficulty pulling the
gearshifter into neutral. That would be key to knowing if there was an
interrupter problem.
Jim