Mariner 50 shift shaft cam problem

[gjeka02]

I have a 1982 Mariner 50 and while changing the water pump I advertantly rotated the shift shaft cam. When I attempted to reinstall the lower unit, the shift lever didn't work.
The shift shaft cam I have is not the one shown in the Mercury service manual. It is sloped and has a flat as well. I have read threads on the internet claiming to re-install the lower unit in forward and others say in reverse. What way is best? How do I set the cam properly to get it to shift?

 

[hotrod53]

Re: Mariner 50 shift shaft cam problem

You need to figure out what position the cam is in and what gear you are in. You also need to figure out which way the reverse lock gear goes back on. The cam should be installed so that when in reverse, the ramp is at its highest point. The ramp pushes the reverse lock up to clamp your motor to the mounting bracket when in reverse, this keeps your motor from climbing up. As far as what gear to reinstall the unit, it seems to be personal preference. I think that what gear is not really the issue, knowing what gear you are in, matching it with the controls, and getting the reverse gear back on in the right position is the key.

There are recent posts regarding this and some have the explanation of how you know what gear you are in by what happens when you turn the prop. Obviously the prop spins free in neutral, but in FWD and REV there is info on which direction it turns and when it clicks. I would start there, rotate the shaft till the prop spins free and put the controls in neutral to match. I went thru the same thing with my lower unit replacement, my reverse lock gear went on about 12 different ways. If that shaft and the controls are out of sync, obviously you will lose gear positions.

 

[gjeka02]

Re: Mariner 50 shift shaft cam problem

Hotrod53,
Is there anyway to tell whether the cam is in the correct position on the shift shaft? I took the cam off to look at it and put it back right back on. If I was off by one spline either way will the that be a problem? Thanks for your response.

 

[charlie741]

Re: Mariner 50 shift shaft cam problem

I have seen this go a couple different ways. When I rotate the shift shaft on the lower unit to select gears it works like this
F - locked on way clicks on the other
N - Spins free
R - Locked in both ways. I like this best so you can wiggle the prop to line up the shaft, but not all motors do that, some lock both ways in forward and reverse.
Another clue is that my LU shift shaft has all 3 very close, only requiring about 1/8 turn to change, the rest of the slack, almost a whole revolution is forward.
I would play around with it a bit and see if you can figure that part out without worrying about the cam, once that is done you can place the cam as mentioned above.
My motor is '74 Mercury 402 and this could all be irrelevant, but I had to figure it out before I learned of this site and I did it just how I told you.

 

[gjeka02]

Re: Mariner 50 shift shaft cam problem

I tried tried to get the shift shaft to move to neutral but it doesn't move. My prop spins clockwise only. I had a hard time turning the driveshaft after I left it over night. I took of the water pump and the vanes where in the proper direction. Re assembled and the shaft turns the prop fine. How can I get the shift shaft to move. It feels like it is spring loaded in the clockwise position and doesn't move CCW at all. I am afraid I will ruin the spline on the shift shaft if I turn too hard with pliers as has been suggested. HELP needed!

 

[gjeka02]

Re: Mariner 50 shift shaft cam problem

Hotrod53,
I can't get the shift shaft in neutral. Since the drive shaft and prop spin CW I am in forward. Should I reassemble in forward? I was trying for neutral.

 

[Demoiselleflyer]

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I have a manual on a pdf file and looked to see if I could help you. Then manual says that if you have to move the shift shaft wrap aluminum foil around it and rotate it carefully with plyers. Sounds like you definately moved it to forward gear from the description in the manual. Having the prop rotate freely both ways is neutral and the prefered position to reinstal the shift shaft. If the splines don't line up it says to tap the shaft carefully with a hammer and tap. It definately makes a difference if you don't get the cam on correctly. I got it one spline off and it caused the motor not to lock down in reverse. I agree with a previous post that when in reverse in should rotate the locking mechanism as high as possible. If you don't get that right, the whole lower unit will have to come off again! I learned that the hard way. Hope this helps. Good luck. Charles

 

[hotrod53]

Re: I

Re: I

I'm sure it can be synced in FWD but I would think that N would be preferred. As mentioned, there are two things in play here, syncing the shift and getting the reverse lock cam on right. I go along with the suggestion of doing them seperately since they both appear to be wrong, get the shafts synced first.

I had the same problem as you are having with the shift shaft, it was really tough to get it to shift, mine appeared to be stuck. I was replacing my lower unit and it was shipped with no gear lube and it sat dry for a while, I assumed that was why it was tough. Once I got it to shift, it seemed to move easier, it did take some doing to get it to go. The guy who was helping me does this often, so he had a shaft that fit over the shift shaft to move it, but at that point I had already gotten it to move on my own. I also had a junk reverse cam from my old lower unit that I could grab on without worry.

I don't know how many splines that you have on your shift shaft, but that's about how many choices you have for the reverse lock cam. Being able to shift it into REV would probably be the best way to determine if it is right. If I remember correctly, going into REV was kinda spring loaded and the cam turned pretty far. As long as that cam had its ramp at the highest point of the ramp, it is on right.

 

[gjeka02]

Re: Mariner 50 shift shaft cam problem

I just tried using aluminum foil on the shift shaft spline to protect it while i tried to turn it CW with pliers. I moves about 10? and then goes back as if spring loaded. Ended up taking the top of the water pump to make sure I didn't mess up the impeller. While turning the shift shaft that 10?, I could get the prop to move CCW freely and ratchet CW when i let go of the shift shaft it was back in forward. It seems to me the reverse cam on the shift shaft is out of position a lot. I guess I have to find a piece to put on the spline and turn it with more force to move it.
Does anyone have this type of reverse cam and know the correct orientation? Can I move the reverse cam so it's in the correct position for Forward, since that is the position I can get the lower unit in?

By the way, prior to this I installed the lower unit and it wouldn't shift out of forward.

 

[gjeka02]

Re: Mariner 50 shift shaft cam problem

Problem SOLVED. Thanks to everyones help and a little ingenuity. I bought a E12 reverse torx socket and it fit perfect on my 3/8" outer diameter spline shaft. I used it to simulataneously while I moved the prop CCW and the spline shaft moved rather easily. Moving the prop was mentioned on another thread. I set the spline to neutral and have no doubt it will fit like a glove when it stops raining and I get a chance to install the lower unit. By the way, in neutral with the prop spinning freely in both directions, the top of the ram is lined up perfect with the front of the motor. I will post the results when I reinstall.

 

[charlie741]

Re: Mariner 50 shift shaft cam problem

Glad to hear, its always good when someone posts the results, so everyone can see what worked and what didn't. Thanks for posting.

 

[gjeka02]

Re: Mariner 50 shift shaft cam problem

Well, I installed the lower unit in neutral with the reverse cam point forward where the high part of the slope starts. Went together well with a little giggle on the pulley. Shifts through F-N-R with no problem. New water pump working perfect. Thanks for all the help. It's fishing time!