Re: 1984 115 Mercury has switched Forward Reverse
If you rotate the shift shaft 180 deg from Neutral, you'll be in Fwd. There is no 2nd Neutral.
This is what happens:
for about 270 deg (or whatever it really is), the shift cam lobe is "low" and does not push on the shift plunger (i.e. it's in Fwd gear).
You can rotate the shift shaft all you want within that range of motion and it'll always be in Fwd gear.
Once you rotate the shift shaft CCW enough to 'find' the detent for Neutral but leave it in Fwd, that's the correct position for the shift shaft if you want to reinstall the lower unit in Fwd.
Shifting further CCW causes the next level of the shift cam to bear on the shift plunger, moving the shift clutch rearwards in the gearcase so that the "dogs" on the shift clutch engage neither forward nor reverse gears.
Shifting even further CCW from the Neutral position brings the highest part of the shift cam "ramp" to bear on the shift plunger, forcing the shift clutch into reverse gear. You're now fully into Rev.
Now, you can STILL turn the shift shaft CCW from here, although it's not a good idea.
It's not designed to do this and I expect puts extra wear and tear on the parts. But if you insist, you can start turning CCW on the shaft and ?Guess What? now you're back in Fwd!!! The shift plunger just "fell" off the "ramp" and is back in the "null" position which allows the lower unit to be in Fwd gear.
Don't forget that there's a pretty strong spring in the shift clutch assy, that is always trying to push the clutch into forward gear. If the shift cam isn't pushing on the plunger, this spring keeps the clutch tight against the ramps on the forward gear. This helps prevent jumping out of gear at higher loadings.
Keep on turning CCW and you'll be right back to where you started, just about to shift into Neutral.
Anyway, that's about all there is to it.
Now, if someone flipped the shift cam over, that's another ball game altogether! But you can figure that out by noting which way the shaft is turning to shift.
Anyway, check 'er out and get back to us, this could get curiouser & curiouser...........ed