Mercury 115 (1973) Lower Unit Shift Spline

[CHICOGUY]

I believe this 'shifting' problem is the result of an impeller replacement.

1.) I currently have the LOWER UNIT off the 1973 Mercury 115, 2 stroke engine L6 "Tower of Power" SN 2483368.

2.) I have cleaned the whole unit.

3.) When I removed the LOWER UNIT, I placed the MERCONTROL Shifter into NEUTRAL.

4.) Now that I have the LOWER UNIT on the bench, I am attempting to place the LOWER SHIFT SHAFT (reference page 9-22 of the SELOC Mercury Outboards 1965-89 Repair Manual) into NEUTRAL, so I can (hopefully) put back the lower unit to the extension shaft and then have the engine shift normally. [My problem is that the MERCONTROL shifting is backwards. When I move the MERCONTROL throttle forwards, it attempts to go into reverse (just grinds, but does not go in) and when I move the throttle shift backwards it then engages decisively into forwards gear.]

5.) I am now attempting to place the LOWER SHIFT SHAFT into NEUTRAL. It is not going. What is now occurring, is that the shaft is in one position, with the WHITE MOLEX PLASTIC underneath it what will move counterclockwise about 15 degrees. The PROP SHAFT will is locked in one direction: if I attempt to turn it Counterclockise it won't turn, and when I turn it clockwise, it just clicks.

Instructions as to how to complete this last problem with this motor would be greatly appreciated.

Thanx
JR

 

[emckelvy]

Re: Mercury 115 (1973) Lower Unit Shift Spline

Your lower unit was in FWD gear when reinstalled, while the shift lever was in Neutral. When you shifted to FWD, it moved the shift shaft right back into Reverse.

What you need to do is manually shift your lower unit from Fwd to Neutral while it's still removed.

To do this, grab hold of the shift shaft with some Vise Grips or suitable pliers. Make sure you have the jaws cushioned with tape etc to prevent marring of the shift shaft splines.

Rotate the shift shaft Counter-Clockwise until you feel the detent and then it'll feel like it fell into a 'notch'. This should be Neutral and the prop shaft will spin freely in both directions.

Note that if you happen to shift to Reverse, the propshaft will spin in both directions but only a limited amount then stop. If you end up in Reverse, rotate the shift shaft slightly Clockwise until you find the Neutral Detent.

Hopefully nobody has messed with the Reverse Lockout cam, which slips over the shift shaft. The correct position for this is, just before the shift shaft is ready to shift to Neutral, the Reverse Lockout Rod from the center section is pointed straight at the mid-point of the 'ramp' on the cam. If it's off, the Reverse Lockout won't work right. Just pull the cam off and re-orient it. There's only one way it can go on and be correct; it'll be obvious if it's installed one or more splines off.

Since your lower unit and shift control will both be in Neutral, you'll have to rotate the flywheel a small amount when reinstalling the lower unit, in order to get the driveshaft to engage in the end of the crankshaft. The shift shaft upper rod mates with the shift shaft right about this time too; jiggle the rod if it won't drop right on.

HTH & G'luck with the reassembly.........ed

 

[CHICOGUY]

Re: Mercury 115 (1973) Lower Unit Shift Spline

Dear HTH & G'luck,

Okay. Thank you. A few more questions.

First, it does take some effort to turn the spline. I had to muscle it with a pair of pliers...it was not easy. I now have it turned, and the bottom WHITE MOLEX plastic piece which goes on the spline, down into the aluminum recess, is now positioned (viewing from the front with the prop in the rear) at 9 O'clock, with its 'Archimedes screw' ramp high point at 9 Oclock.

NOW THE OUTPUT PROP SHAFT MOVES BOTH WAYS EASILY (CCW AND CW). I 'believe' the God of Mercury has seen fit to allow me to shift into neutral...

Now. There are TWO plastic pieces we have to be concerned with here. The first is of course, the WHITE MOLEX plastic piece described above, the SECOND, is a dark BLACK plastic piece which apparently sits on the top of the WHITE MOLEX.

This DARK BLACK plastic piece has two holes, and unlike the WHITE MOLEX part, (the WHITE MOLEX actually FITS onto the splines of the shifting shaft)--the DARK BLACK plastic piece has one hole (that fits or goes over the shift spline shaft...but does not have any spline corregations to fit...it's just a hole) and another hole directly to the front of it. [Apparently, the SHIFT ROD coming down from the engine fits into that].

I did not feel that 'notch' you indicated. But again, my OUTPUT PROP SHAFT now turns both ways. I am 'assuming' it's in neutral. *I must reiterate, and do hope it is right, that the WHITE MOLEX piece is pointing to 9 O'clock (viewed from the front). What I mean by this, is that the little ramp (an Archimedes Screw ramp, is pointing LEFT at 9 Oclock. Is this the correct orientation?!?? Analyzing this, my gut feeling is that it should be pointing forwards (6 O'clock position) to align with the BLACK PLASTIC FRONT HOLE, which I assume the shifting shaft comes down and aligns to the TOP of the ramp, so that when you shift, it pushes down on the ramp to turn the unit. In other words, right now, the 'high point' of the WHITE MOLEX piece is at 9 O'clock for neutral. Is this correct? Or should it be at the 6 O'Clock position (or some other orientation?

Now, my final questions are several:

1.) How does the BLACK PART PLASTIC FIT ON?
2.) Does it need to be glued (tacked? Let's say a minimal dab of silicone or glue?)
3.) How about the two notches on each side (one at 9 Oclock and the other at 3 Oclock)--they 'appear' to fit in the dovetailed recesses in the aluminum case--however; currently I cannot push down due to the WHITE MOLEX piece which stands too high to get the BLACK PLASTIC piece notces to fit in their respective slots.
3.) Do these part get any grease or any lubrication of any type? I've cleaned them to the nth degree (you can put them in your mouth. Go ahead...try it) and wonder if being 'dry' might be an issue.

4.) How does the BLACK PLASTIC piece stay stationary when re-assembling the Lower Unit? (I'm certain it is going to dance like a Spanish dancer when that time comes)...

5.) Why the hell hasn't anyone put a cogent piece either in The SELOC manual or on this list to explain this. Trying to access and search this database is not user friendly. I could spend hours, and still not get what I am seeking.

Hope this helps.

JR

 

[Chris1956]

Re: Mercury 115 (1973) Lower Unit Shift Spline

JR, There is a black molded piece of plastic that acts as a shift rod guide. It keeps the upper shift rod in the correct place to contact the lower shift rod. The brass fitting on th upper shift rod fits snug into the black plastic piece. Place it in the midsection prior to reassembling. Stick it there with some grease or silicone.

 

[CHICOGUY]

Re: Mercury 115 (1973) Lower Unit Shift Spline

Chris,

No brass thing on top of back plastic piece.

Also, how about the position of the WHITE MOLEX CAM? How is that orientated?

JR

 

[CHICOGUY]

Re: Mercury 115 (1973) Lower Unit Shift Spline

Is this the proper orientation for the WHITE MOLEX Shift Cam *(for NEUTRAL)?