Mercruiser Shifting Issues

[tony_tony]

Good morning I have a mercruiser 350 mag tbi alpha 1 and I'm having a problem with the shift interrupt switch I've replaced everything from the shift cables to the ecm and even the harness and the shift plate I'm honestly at a loss right now I was wondering if there is anything I'm missing

 

[Bondo]

Good morning I have a mercruiser 350 mag tbi alpha 1 and I'm having a problem with the shift interrupt switch I've replaced everything from the shift cables to the ecm and even the harness and the shift plate I'm honestly at a loss right now I was wondering if there is anything I'm missing

Ayuh,..... Welcome Aboard,...... What sorta problem,..??

 

[Scott06]

How about a little description of what was happening , exactly what was replaced in what order (oem parts or aftermarket), and what is happening now .

Throw on thing to try assuming it is a gen 2 drive - if you have the shift assist cylinder on there try taking it off. I think it was intended to center the dog clutch in neutral have seen comments of it interfering with shifting

 

[Sea Ray Mick]

I'm having the same problem with a "79 Sea Ray 240 Sundancer w/Merc. 260 and Alpha One Gen 1 Stern Drive.
Initially I thought there was shift cable issues as it wasn't engaging the outdrive (fwd or rev.) so I removed the outdrive to inspect the lower shift cable and do a thorough upper gear inspection, which I did; as I was preparing to separate upper from lower units and inspecting the gimbal bearing, I used a flashlight to look inside, it was then I realized the coupler was wiped out (!@#$%^&).
I had already reset the adjustments on the cables to their original positions and followed the instructions in the manual as well as following instruction on two good YouTube video's to make sure I got it right.
I have since replaced the Engine Coupler and both control cables with Quick Silver Platinum Cables and adjusted according to spec.
Now I cannot get the interrupt switch to work properly; FWD & Neutral work good, but when I try to get reverse to engage the interrupt switch rides high on the mechanism - I've tried adjustments in very small increments until I've got it the best it seems to want to adjust.
Without starting the motor reverse doesn't seem to want to fully engage, but when I put the water hose on it, it will actually engage reverse but it doesn't feel or sound right. I've found that I can wiggle the lower shift cable and the interrupt switch will eventually return to the correct position, but it doesn't "interrupt" the engine during the shifting procedure like its supposed to. This unit was working fine before I changed the coupler and I've spent HOURS going over the video's etc readjusting trying to make it work right, with no success - I'm at a loss here, I can usually fix anything but this one has me baffled for sure. Been trying to get a boat mechanic to come look at it and help diagnose the situation but so far no help - planning to pull the lower shift cable tomorrow and look for problems with the cable.
This unit also has the revers lock mechanism on and seems to have excess play in the control arm; wondering if that could be contributing to problem.
Any help figuring this out would be greatly appreciated - there's some pretty intelligent folks on this forum and I've followed a lot of advice ya'all have contributed - I appreciate all your expertise and experience.

Thanks in advance
Mick

 

[kenny nunez]

Since the shift slider travels to the rear for reverse in the housing sometimes salt residue or corrosion will build up inside the cavity. After you remove the drive be sure that the cavity is clean.

 

[Sea Ray Mick]

Since the shift slider travels to the rear for reverse in the housing sometimes salt residue or corrosion will build up inside the cavity. After you remove the drive be sure that the cavity is clean.

Thanks, good advice...
I cleaned everything very thoroughly before I put it back together the last time - after installing the coupler.

 

[Bt Doctur]

And it should never operate on land and only when coming OUT of gear in the water

 

[Sea Ray Mick]

Pulled the Stern Drive off yesterday and pulled the core wire out of the lower shift cable; before pulling I checked it for stiffness and it didn't feel very smooth so I striped it down from inside and pulled the core to examine it.
I didn't find any fray's but on the cable guide end, about the last 16-18", it appears that there are some fairly abrupt bends in the core wire, not enough to call them "kinks" but enough (I think) to cause resistance while shifting. This could very well be the reason why I could "wiggle" the cable where it wraps around the exhaust and enters the cable guide, and the interrupt switch would slowly return to the neutral position. I'll find out on Monday when the new lower shift cable arrives and I install it.

 

[Sea Ray Mick]

I am also having a hard time find proper routing of the lower shift cable for this particular model year. From what gather, it should be '78 - '85 - changes seem to have been made sometime during 1973 model year.
Any illustration (pic's) for this routing would be greatly appreciated since I don't want to install the new cable with too short of bends and end up causing the same problem all over again.
Note: on this particular Model the shift plate is mounted flat (horizontal) across the back of the engine, directly above and anchored to the flywheel/bell-housing. see attached pic

 

[kenny nunez]

When the cable is pushed in it will hit the back of the flywheel housing, it then has to be pulled to the starboard side then routed up to the shift plate.

 

[dubs283]

The lower shift cable comes through the gimbal housing and routes between the flywheel cover and the exhaust y pipe

Then routes up and between the exhaust elbow/riser gap next to the remote shift cable and attaches to the plate

 

[Scott06]

See attachment from factory manual

I found it best to pull the inner core out, then push a weedwacker wire up the cable to the shift plate and tie it off, pull the cable outer sheath out through bellhousing. Use the weedwacker wire to guide the new outer cable up and around the exhaust and flywheel cover

 

[ROY WILLIAMS]

I am also having a hard time find proper routing of the lower shift cable for this particular model year. From what gather, it should be '78 - '85 - changes seem to have been made sometime during 1973 model year.
Any illustration (pic's) for this routing would be greatly appreciated since I don't want to install the new cable with too short of bends and end up causing the same problem all over again.
Note: on this particular Model the shift plate is mounted flat (horizontal) across the back of the engine, directly above and anchored to the flywheel/bell-housing. see attached pic

I was the MCM470 engine Wellcraft 1978 . the picture is the same of the throttle cable .. and the cable switch ... the outdrive cable is not doing the picture ? I was the shifter cable of the fwd and the 6 inches inside that switch picture ..
the outdrive is the fwd of the finger is straight ....

 

[Sea Ray Mick]

Thanks for all your responses and illustrations....
From what I gather the cable needs to run up from the transom plate and "between" the exhaust riser and the rear of the head (starboard side) and looped around behind the riser to the shift plate - and anchored somewhere in-between the transom plate and shift plate - that's where I'm getting lost - I'm not finding the anchor point. seems there should be a cable anchor somewhere on the back of the head or riser. If I anchor it to the transom it makes the cable too short and seems to stress the cable. Maybe there's something on bell housing, near the starter that I'm missing, or I simply just need to add one somewhere in that vicinity - the illustrations, AGAIN, are not very clear - the routing is pretty clear but the anchor point is vague at best.

 

[Bondo]

Ayuh,.... The cable is anchored on the ends, 'n nowhere in the middle,....

 

[Sea Ray Mick]

Ayuh,.... The cable is anchored on the ends, 'n nowhere in the middle,....

So somewhere near where it comes through the transom plate or near the shift plate - I'm not seeing anything near either of those points.
I can take some close up pics if it will help solve the mystery here lol
Thanks for your reply, much appreciated

 

[Bondo]

So somewhere near where it comes through the transom plate or near the shift plate

No,.... Just the ends,.....

 

[Sea Ray Mick]

Well, new conundrum.....
Installed the new lower shift cable with success, no issues.....
But.....now the control cable isn't working.....hmmmm......
It was working fine before I changed the lower but now it wont shift at all.
As I stated before, both the control cables are brand new Quicksilver Platinum cables and everything was working fine, except for the cutout switch issue.
I know the lower is working right because I can shift it manually and engage the prop in both direction.
So what the heck could have caused the upper to "disconnect" after installing the lower cable.
It feels like the shift assembly is stuck in neutral, really smooth, zero drag like one would feel when engaging.....weird...
I may be getting a message here on this boat lol
I'll be taking the controller off this morn for further inspection.....I simply can't imagine the Quicksilver cable to have broke already without any use.

 

[kenny nunez]

If you anchored the shift cable that comes from the control box that can cause a problem. It has to be able to move in bot directions.

 

[ROY WILLIAMS]

THE SHIFT HANDLE IS THE FORWARD GEAR... AND THEN THE ADJUSTMENT CABLE OF THE OUTDRIVE IS THE STRAIGHT CABLE OF THE FINGER OF THE STRAIGHT UNDER THE BELLOWS ..