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redsnapper386

Regular Contributor
guys i have a 1987 alpha-1.i can hear it trying to go into reverse but no go.forward is good.the shift cable is new.the cable at the shift controll module is centered up as it should be.it seems that i have no more adjustment left at the controll mod.the controll module is also new.would there be a problem in the upper unit of the drive.need instructions.thanks in advance
 
possible the helm cable has stretched, or frayed inside the casing. or, worn through the inner casing at a bend.

is this new controller specifically for Mercruiser?
 
Here's a very simple procedure to begin eleminating potentials.

Start by checking to see if the prop shaft Dog Clutch sliding sleeve can maintain neutral and yet reach the travel needed to engage both FWD and REV gears.

With the lower shift cable unattached from the SA mechanism (or it can be left attached while you make adjustments), and with the drive lowered all the way down, have a helper sping the prop back and forth. (drive is lowered to avoid gravity against the sliding sleeve)
Have the helper continue to go back and forth... back and forth.... back and forth.... using a rythm of sorts.
Doesn't need to be much...... Just keep doing it.

While you are inside the engine bay, manipulate the lower shift cable towards a FWD gear engagement, and until you can just hear the sleeve touch the FWD gear dog teeth. You will hear them just begin to click!
Note the cable travel required in order for the sleeve to just touch the dog teeth.

Now manipulate the lower shift cable towards a REV gear engagement, and again until you can just hear the sleeve touch the REV gear dog teeth.
Again, note the cable travel required in order for the sleeve to just touch the dog teeth.


Now calculate where the center of this cable travel would be.
This will be your prop shaft sliding sleeve "Neutral" positon that all other OEM adjustments aim for.
The OEM does NOT explain this procedure for reasons of their own. Perhaps it's too simple! :D

Now re-connect this lower shift cable back up to the SA mechanism while the spring loaded cam is also in Neutral.
Now adjust your helm control shift cable to fit this adjustment.... and again, Neutral is the goal.

Assuming that cables are good, throttle/shift unit is good, and no other issues elsewhere...... if you still cannot engage REV, then there is likely an internal issue with the lower unit.


.
 
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Bill, that's why I suggested that he first determine if the sliding sleeve could reach neutral, and then make full travel in either direction for a complete dog tooth engagement.
If that doesn't do it, then he likely has an issue inside.... perhaps the shift rod, shift spool, or perhaps even the dog clutch teeth.
Would you agree?
 
i need to add that i installed the newer style of shift module from mercruiser which is the push button style.the old module was the roller style which is no longer available.thanks for help.
 
redsnapper386 said:
i need to add that i installed the newer style of shift module from mercruiser which is the push button style.the old module was the roller style which is no longer available.thanks for help.
Click to expand...
The shift module and/or micro switch (if you are referring to the SA... i.e., shift assist) are likely not your problem.
Not unless you somehow fiddled with the linkage and it is now binding up somehow.
This is why the test that I wrote out for you will either show what's wrong with the cable adjustment, and/or will eliminate certain potentials.

BTW, the Merc SA is designed to aid in a shift from gear back into neutral..... not for gear engagement.
 
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