Lower unit replacement gone bad

[Steve01]

I have a 1975 Merc 85 hp with a bad lower unit. Placed controls in forward position as instructed and removed lower unit. I acquired a 90 hp Mariner lower unit that had been placed in the forward position prior to removal. I greased the end of the shaft and installed the replacement unit. It went together with no problems except the last quarter inch which I drew together with the bolts. I placed the controls in neutral and started the engine -OK so far. Now I put it in reverse and it engages OK, but when I accelerate the engine raises out of the water, the lock-down did not engage. Now, I place it in forward position but it does not engage - it only rattles like the gears are slipping by each other. What did I do wrong and how can I fix it?
Steve

 

[fastjeff]

The shift coupler is screwed up somehow and not allowing full forward engagement. The flip up in reverse is caused by the 'hook' not grabbing the tilt pin.

You'll have to drop it again a nd see what's happening.

Jeff

 

[spiderman]

Yep,I would say the same the shift coupler

 

[Steve01]

Do you know where I can get a diagram of the lower unit to see how it should go together?

 

[music tinker]

Clean the grease out of the the shaft hole and of the shaft.The fit is so tight your causing the gears to disengage.

 

[racerone]

Remove the replacement lower unit.------Verify that it shifts properly --------- forward / nuetral / reverse.----Then verify that it is in forward and install it.-------Verify that it shifts to nuetral before installing all the fasteners.

 

[fastjeff]

Rotate the LU half CCW until you take all of the slack out.


Jeff

 

[hotrod53]

and if your hook isn't grabbing in reverse ... and it should ONLY grab in reverse, the cog with the steps in it that goes around the shift shaft is either worn out, broken, or installed wrong. The highest part of the ramp should line up with the reverse lock rod when in reverse. If you installed the LU not in the right position, the cog will most likely not be aligned up either. Mine was all messed up when I dropped my unit too, its a PITA for us shade tree outboard mechanics!

I surely wouldn't call it "gone bad" yet!