1996 merc IO alpha cam on shift cut off switch moves and I cannot get into neutral only in water

I have a 1996 alpha IO .



I replaced the steering cable and when I used the boat next it would stay in gear.


It seems like the easy answer to my problem would be the shift cable is bent some where from me pulling steering cables through but I cannot validate that. I trailer the boat. With the water hose attached in driveway everything seems to shift in out of gear just fine. I have read the manual I have and cannot figure out.

When I am on water and I put the boat in forward it works fine until I try to put in Neutral. The plastic part (may be called Dentent) that the shift cable cut off switch seats into moves under power. It gets stuck there. This prevents the cut off switch from engaging because it is not in the cutout seat.. I put it in reverse a little and it pops in place. Sometimes I go too far and it kicks into reverse which is taking a toll on my outdrive I am sure. This also happens sometimes in reverse and I do the opposite.

I cannot figure out what the point of that part being able to move is. It is clearly made that way with compression metal band on both sides.



Any ideas appreciated.

Steve

It should engage only on the water and coming out of gear. The pressure of the prop on the gears cause it to move in the water and not on the trailer.

The shift bracket, see where the cable from the control connects to it. Remove it and then shift the lower using the lower cable.

If it shifts good on the water no problems then the cable coming from the control went, is bad.

Does the control cable to the bracket move freely disconnected?

What is idle on the water in gear on a warm motor ?

There is a method to my madness, so just bear with me a bit to trouble shoot the problem and not just throw parts at it.

To better understand what you are dealing with here is how it works.

In the lower unit forward and reverse gears have a saw tooth configuration on the inner
diameter of the gears. There is a clutch dog which has the same saw tooth configuratio inbetween the gears that moves into forward or reverse when you shift. When in the water under load the cyntrifical forces on the gear and the clutch dog make it near impossible to disengage by just shifting. So a micro switch is used to momentarilly short the ignition to ground which dissrupts the gears and clutch dog and allows them to seperate with the shift cabels.

So what may be happing is the micro switch is not doing is job.
To test the switch, start engine and push the micro switch in, the motor should stall.
If it does not then the switch or wiring is defective. If the motor stalls then it is either a shift cable adjustment or a faulty cable.

When you installed the sterring cable did you alter/restrict the routing of the short shift cable?

To all.

I thank you for giving me a better understanding.

I keep thinking I did something to shift cable also when I ran steering cable but I do not see how it is restricted.

The cut off switch works. It only does not work when the cam is in the wrong position not allowing it to work.



I have not had a chance to put in water again yet.


I took apart the throttle cable and it seems to move freely. I also moved arm to cable that engages stern drive and it also seems fine. ( not in water, I know )

I decided to put it back together and to try shifting without shift cable like was suggested on the water.

Now it gets interesting.


I did not adjust anything on shift cable yet but the spring arm on top ( like screen door arm ) does not line up. I have to make the cable a littler longer simular to putting in reverse.

I do not know if maybe tention is there on purpose and for some reason I did not actually put in reverse to try . I turned the barral adjustment on the tread of cable to make longer and line all up.

IS it posible the adjustment changed some how with age and me moving the shift cable around which I assume I must have done when I put in steering cable?

I cannot wait to bring to water and see what happens.


What do you think?

thanks
Steve

I am not at my computer now but I will post a complete adjustment proceedure later and some additional information that will assit in understanding a bit more. Unless someone else posts the info before then.

Here is a procedure that I have used with good success.
One thing to bear in mind is that if it used to shift properly, and now it doesn't (unless you have been playing with it!), then something has gone out of whack and may need service. Could be your lower shift cable, upper or lower shift shaft, or something in the lower gearcase. Is the drive oil clean and no metal?
cheifalen's question about your idle RPM in water in gear is important. If its much more than about 600 RPM, there may be too much resistance when you try to shift out of gear, and the shift interrupt switch arm will move out of the detent against the spring, and it will die.
When you have the upper cable disconnected from the vertical shift arm, you should be able to move the lower shift cable and arm very easily, almost no effort with one finger. If the lower shift cable has not been changed out in 10 years or more, suspect that it needs changing.

Short Shifter Cable Adjustment Procedure
Trim out drive up 2 inches from all the way down.
Take keys out of ignition!!!!!!!!!!!
Have a second person stand at the prop.
Remove the short shift cable from the shift bracket.
After the cable has been removed, push the plastic cable end all the way in.
Have second person rotate prop counter clock wise until the prop is fully engaged and wont turn anymore. Maintain light effort on shift cable plastic end pushing it to keep forward engaged.

Measure the distance from the center of the brass barrel bolt to the center of the round mounting hole in the plastic end. Adjust barrel bolt to make that distance 6 inches. No more no less! In cases where the shift cable is old but still works well you can adjust this dimension to 5 5/16”. NO MORE.

Put shift control handle in forward FULL throttle position.
Remove the control shift cable from shift bracket at this time.
Install short shift cable back onto bracket at this time.

Take the shift control cable and adjust the barrel bolt so it fits perfectly back into the shift bracket.
Before installing it turn the brass barrel bolt 4 complete turns away from the plastic end and reinstall into shift bracket.

Now put shift control handle in the neutral position.
Have second person spin prop, it should spin freely.
Put shift control into the forward detent position at ~ 10:00 position. NO FURTHER.
Have the second person rotate the prop counter clockwise. You should have solid engagement with no ability to continue to turn the prop.

Now shift back into neutral. Prop should spin freely with no clacking or clunking.

Now shift to reverse to the 2:00 o’clock position detent. NO FURTHER!!

Have the second person spin the prop clockwise.

If you have positive engagement with no clunking or jumping out of engagement, you are done.

If it does not fully engage into reverse than look at the shift bracket where the short shift cable mounts and there is a slot. Loosen the 7/16 hex that is touching the bracket and move the stud upwards so you are pulling the short cable out a little more.

Try this and retest in water under load.

Good luck,
Rod

Thanks Rod, That is my write up, good to see others are using it.

One other point. This year engine should have the power piston/shift assist the pushes forward and reverse and is connected to the control shift cable connected to the shift bracket. Is this present and is it functioning?

Also I totaly agree that if ti worked before the installation of the new steering cable then something else may be the cause of this.

Maybe some pictures of the components may help.

kghost;
I have used your writeup a few times with good success. Sorry I should have acknowledged you as the author, but I did not remember where I had gotten it from!

stevesoy;
You said:
"The plastic part (may be called Dentent) that the shift cable cut off switch seats into moves under power. It gets stuck there. This prevents the cut off switch from engaging because it is not in the cutout seat.. "
Something does not add up here. For the engine to run the switch has to be in the detent. If its not, the switch should be cutting out the engine.
If the engine still runs in this condition there is something wrong with the switch or the wiring.
Also if I understand you correctly, putting it into gear causes the detent plate to overcome its spring and the switch comes out of the detent.
if that is whats happening, that is a clear indication that there is too much resistance in the lower cable or the shift shafts, or the lower gear case.
Again, the first suspect would be the lower shift cable.

Rod

I thank you all

I have been out of loop playing with it for awhile. Bad weather in NY and job stuff.

I followed the adjustment steps and things were out of adjustment. maybe due to wear.

I believe it is switch. I really did not get how it worked but when it is running and I move plastic and switch out of dendent and it does not stall. I would say it was the switch all along not doing its job like suggested and wear and tear on the cable .

Every week something else breaks. Joys of boat ownership. If it was not for the help I found here I would have packed it in awhile back and I thank everyone.


It is running not so good now in my driveway but I am low on gas and I must have put it in and out of gear 20 times to make sure the cable was adjusted correctly.


Anyway

I will replace the switch this weekend and bring it to the water and let you all know.


Thanks

Steve

To all,

I took the boat out in water and everything shifts fine. I believe shift cable was out of adjustment but the story falls under ( you cannot make this sh-t up ) as I brought part of this problem on myself.

I went to buy another switch to find out they stopped making them 10 years ago and would have to buy the whole new dendent unit for $ 140.00. I did buy it and took it home.

Before installing I traced the wires from the switch and realized what happened.

AT the beginning of the season I posted problems with my motor cutting out in my driveway and blowing a fuse. After much work ( and not knowing what the shift switch is at the time ) I traced a short in the purple wire to iginition and by passed that part by the boot to coil and my motor worked. I did not notice a shift problem to months latter. I now know, the wire I bypassed was also the lead to the switch so it was not working because it was not hooked up. I put all the wires back to orginal and put the orginal switch in. I activated switch while running and it stalled. I did some adjusting of metal band and ran the engine. It seemed to shift fine and I did not blow a fuse. I tried in water and it worked fine so I never put in new dendent unit .I assume the dendent was out of postion in the spring in my driveway somehow was activating cut off switch and it shut off. I still have no idea why that would blow a fuse. Evertyhing is adjusted as instructed and working but I still worry about what made the fuse go back then since I did not change any part and only adjusted cables.. IT would all make sense if the switch was broken and causing a blown fuse but that is not the current case at this time anyway.

If it happens again I will replace with new swtich dedent unit but I am returning it for now.

I thank people for helping me understand how the switch works and I hope you all have a good laugh at me. I know I did.

thanks Steve

stevesoy said:

...... It is running not so good now in my driveway but I am low on gas and I must have put it in and out of gear 20 times to make sure the cable was adjusted correctly.

Click to expand...

Steve, just a friendly FYI for you regarding your SI (shift interrupt):
As it turns out.... you apparently found out what the issue was..... but my guess is that you messsed with some adjustments in the interim.
If so, you'll want the boat in water in order to adjust this correctly.
You'll simply spin your wheels in the sand if you try to adjust while on the trailer.
Got to have that prop thrust!

******************

I'm coming in very late on your thread here, but since I have responded to similar threads in the past, thought that I'd chime in.
Some of this is my own cut'n paste..... sorry if redundant... but perhaps one more explanation and/or method may help solidify this for you.
At least take a quick read... if nothing too interesting... just pass on it!

As you now know, the prop thrust (while in the water) is what wants to keep the Dog Clutch teeth engaged during a return to neutral shift.
It's all about over-coming the prop thrust with Dog Clutch type gear engagement drives.
Going into gear is never the issue!

As Kghost mentions, the resistance of the lower shift cable.... (due to the sliding sleeve wanting to remain engaged with either FWD or REV driven gear), it what's causing the cam lever to move.
The more resistance of the Dog Clutch....... the more force behind the cam movement.
Fast FWD thru the cam/micro-switch explanation....... bla bla bla....

The moment that the micro-switch causes the Ignition to stumble engine RPM, is the same moment that the sliding sleeve is now free to disengage from whichever gear teeth it has been engaged with.....(be it FWD or REV).
Once disengagement has been achieved, resistance is eliminated, the cam then returns to it's "neutral" position, the micro-switch opens, and the Ignition system is restored, bla bla bla.... (and I know you get this!)


NOTE: With Dog Clutch engagement, any shift from gear back into neutral must be done quickly and concisely.... No fooling around.... No slow shifts. When you make up your mind to shift....... SHIFT!
Quicker the shift.... the less time the ignition will be interrupted.

******************

I like Kghost's adjustment method because the OEM measure does not always work out well.
However, I believe that there is a slightly more accurate method if you are open to hearing it.

Like suggested, you need a second person at the propeller.
While this second person spins the prop back and forth... equally and quickly....., the person inside of the boat will move the lower shift cable just until the sound of the sliding sleeve contacting the FWD driven gear can just be heard (key point here).
Take note of where the cable travel is. .... or mark it in whatever method you wish to use.

Now while still rotating the prop back and forth, and again equally and quickly....., move the lower cable in the opposite direction until you just begin to hear the sliding sleeve contact the REV driven gear.
Again...... take note of where the cable travel is.

When these two measurements are split (divided equally) and applied to cable travel......, this is about as close as one can get to positioning the sliding sleeve equal distance between the two driven gears..... IOW, absolute neutral.

My take is...... we want to position the SI hardware for when the sliding sleeve teeth just begin their engagement, not necessarily when they have become fully engaged (has to due with shift spool, slack, linkage, etc.)
This is where our two methods somewhat deviate from one another..... yet have similarities!

Now make your adjustments to all of the SI components accordingly.


Give this method a try.... you may find that it works quite well.
Perhaps use it in conjunction with Kghost's method.
If not.... nothing lost but a few extra minutes of your time!


.

Steve;
In my first post on this topic i said: "One thing to bear in mind is that if it used to shift properly, and now it doesn't (unless you have been playing with it!), then something has gone out of whack and may need service."
That should have been your clue that changing the switch wiring in the first place may be causing the trouble.

It is generally inadvisable to mess around with the manufacturer's wiring, unless it is a known published upgrade, and you are experienced with the mod.
The shift interrupt switch is there for a reason, and even if you did not know what it was, I am surprised that you would arbitrarily defeat it.

just my thoughts,
Rod

Rod, was that an A$$ Chewing for Steve????

Actually, you make an excellent point, and I don't disagree one bit!
What's that old saying....... If it aint broke, don't fix it!

Be that as it may, it looks like Steve got past this, and apparently all is working now.

RicardoMarine said:

Rod, was that an A$$ Chewing for Steve????

Click to expand...

Rick,
I did not mean to come across nasty; my only point was that Steve had the keys to the root of the problem in his hand the whole time, but failed to give us the whole story about what had been done to the engine previously. Meanwhile we were all trying to diagnose the problem assuming the interrupt switch was wired in and doing it's job.
He could have saved himself aggravation and the rest of us a lot of time by giving us the complete picture up front.

Rod

If you go back to one of my earlier posts I specifically asked and instructed how to test the switch. What he omitted was a completely seperate post for a different issue which resulted in this problem. I would hope he learned some good info from all. We collectively gave him more info than some working in the field know.......lol

I have not check this in awhile.


I have not checked this in awhile.

To All,


Yes I know just enough to get into trouble and I seems like I am a idiot but I am just not experienced which is what I thought these forums are all about . . I lesser man would not have admitted the truth but I thought it would be helpful to others and interesting. And yes I did not completely get how to check the switch earlier enough in the process even if it was stated.




If you think you wasted your time which seems to be implied you did not. I have a better understanding now but honestly there still in not an answer to what caused my original blown fuse problem in the spring in the first place.


For the record, I did not intentionally disconnect the interrupter switch if anyone is thinking that or any switch not knowing what it was... Yes I did not know what it was at the time when I posted problems about my engine blown fuses in the spring and shutting down and not one person brought up the switch as a possibility that I recall. I did not know anything was spliced in the wire I thought had a short in it that I by passed. It was not like I am by passing this switch and the heck with the switch whatever it was.
I was blowing fuses and yet I put everything back the way it was with original switch recently and it seems to work and does not blow a fuse YET. Yes I adjusted the cable with everyone’s help but still have no clue about the blown fuse part

To idiot me, even if the switch was not in proper position in dendent ( shutting off engine ) what does that has to do with blowing a fuse.

I am tempted to move the switch in engaged position and try to start it in an attempt to have closure to all of this by seeing if it blows a fuse but I do not want to risk screwing it up.

I thank you for the help.


Steve

stevesoy said:

... even if the switch was not in proper position in dendent ( shutting off engine ) what does that has to do with blowing a fuse.

Click to expand...

Steve;
That is a great question. There is no reason why the interrupt switch should blow a fuse in normal use. Who knows; you may have an intermittent wiring short somewhere, which will be a bear to find even when it does re-occur, if it does.

And I did not mean to seem to be picking on you necessarily; I just recently rejoined the forum and had no knowledge of your post back in the spring.
And yes you are correct, that is what these forums are all about; people helping people.
Personally I have learned a lot on this forum over the several years I have been at it, and I like to think I may have helped a few folks out in return along the way. My attitude is you can never know too much about these things. And who knows but that little tidbit of information you read on the forum way back may save your bacon one day out there on the water when your baby acts up for no apparent reason!!

In the end, it is good news that your problem seems to be licked. Let's hope it stays that way. And please, don't be a stranger to the forum.

Best regards,
Rod

Dear Rod,
I thank you for the support
Steve