Need help with a 1976 mercury 4.5 hp

mmumm

Recruit
Joined
Apr 11, 2016
Messages
3
I recently took motor apart and I'm in the process of putting back together. I am having trouble getting the neutral, forward, and reverse lever shaft with gear on the end lined up correctly with the gear that is on the end of the shaft that goes down to the lower unit. If somebody could get me a pic of how the two gears are supposed to line up that would be great.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
I had one of those back in the day but didn't have to work on it. However, I would assume the shifter is common to all Mercs in that the shift shaft goes through the mid section and then mates to a short shaft in the lower unit which protrudes half an inch (give or take) above the front top of the LU (have to drop the LU to see it). Otherwise the shaft is uncoupled from the upper shifting arm under the carburetor and the whole shaft comes out with the LU.

The shift shaft, regardless of the type mentioned above should then have a splined lower tip that is inserted in a splined hole in a flat plate referred to as the shifter cam and has an upper and lower alignment hole in the LU casting. The cam has 3 detents, each a different distance from the pivot point (where the shaft enters) and as a result, positions the clutch dog mounted on the prop shaft in one of 3 positions which are F shortest, N mid, and R farthest detent.

The shaft is merely pushed into the cam with no locking mechanism, so much if any upward pressure can pull the shaft out of the alignment holes (one above and one below the cam as mentioned) and cause the cam to misalign from the shaft. The cam follower in the front of the prop shaft is liken to a dull pencil and rides in these cam detents, forced there by a spring inside the prop shaft and effects the shifting by moving the clutch dog to the correct gear position. This spring action is what makes it difficult, besides the fact that you can't see what you are doing, in attempting to stab the shaft back into the cam if it becomes dislodged. The solution is removal of the R gear and bearing carrier with the prop shaft and with the parts mentioned and finally the F gear and shims (which can be slid out under the drive shaft pinion gear) to allow you to get at the cam and with luck maneuver it back in alignment with the shift shaft so that it can be pushed all the way in and connect the two alignment holes and the shifter cam. Pay attention to any shims you find and ensure that you get them back where they were upon reassembly.

If I missed the point of your question excuse me. At least it was an exercise for maintaining my typing skills before I loose them.

Good Luck!
 
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