Shift Shaft/Lower Unit Help

[AugustMoose87]

Long story short, I've taken my 1978 800 Merc and given it an overhaul. I've just finished replacing what needed it in the water pump, and am trying to get my lower unit put back in.

The good news: I've managed to "correctly" (ie everything lined/hooked up) about 8 times now.

The bad news is my shift shaft always seems to be off. Based on what the prop did when I spun the motor, it would seem to be stuck in reverse. When the lower unit is off, I have spun the shift shaft with pliers.

If I twist the shift shaft counter-clockwise, I get to a point where I can feel/hear a click, and can spin the prop counter-clockwise, and it spins the drive shaft, or I can spin it clockwise and it "clicks" as I spin it. Then I can spin the shift shaft about 120* clockwise to a "soft" stop, where it feels like I might be able to keep going, but don't want to force it for fear of breaking something. At this stop, as well as all of the points in between, moving the prop produces the same results.

Two other things worth noting - First before the overhaul, I had no problems with shifting gears. Second, although I intended to open and check/clean the gear case, I wasn't able to (another story), point being that I haven't made any changes to the internal workings of the gear case.

I've spent literally all of my free time this week trying to figure this out. Can anybody help me???

 

[Moody Blue]

Re: Shift Shaft/Lower Unit Help

The good news: I've managed to "correctly" (ie everything lined/hooked up) about 8 times now.

The bad news is my shift shaft always seems to be off.

Somewhat of a contradiction, yes?

From your description it sounds like you are in forward gear, not reverse. In reverse, the prop shaft and drive shaft are engaged in both directions. In forward gear, the prop shaft will ratchet in one direction and engage in the other.

The shift shaft has ALOT of play in forward gear, just a little in reverse and none in neutral. There is a positive detent stop when you rotate the shift shaft into neutral position. It will take some effort to engage neutral because you are pushing against a spring in the LU. Careful not to damage the splines with the pliers. I use a ratchet and small socket (don't recall the size) that fits the end of the splined shaft perfectly.

Because there is soooo much play when in fwd, I like to reinstall the LU when everything is in neutral. No ambiguity about how everything should line up.

 

[AugustMoose87]

Re: Shift Shaft/Lower Unit Help

went out and found out it was an 11/32 for the shift shaft, and managed to pop it into neutral and revers (I was in fact in drive). Thanks for the help, i just didn't want to force it, break something and then be up the creek.....

Now I just have to finish up with my transom rebuild and take it out for a spin. Thanks again for the help.