1969 20 hp merc lower unit removal

I am trying to remove the lower unit on a 20 hp merc. I have all the nuts off but it only drops about a half an inch. I have read some posts that some units get stuck on the drive shaft and I may need to pry. I am concerned about the shift shaft does it just pull out or do I need to disconnect something?

Re: 1969 20 hp merc lower unit removal

Hi

The shift shaft should just pull out.
Be sure to put grease on all splines when you put it back together.

Another thought is that your drive shaft spline is wore into your crankshaft. So you may have to put the engine in reverse and take the plug wires off. The turn the flywheel counter clockwise while locking the prop shaft form turning to try to release locked up splines. I hope it is just carboned up and needs a little pry or light tap to get it out.

Re: 1969 20 hp merc lower unit removal

I usually try tapping a rubber mallet on the bullet part of the lower unit. Do not bang on the anticavitation plate or the skeg as they are prone to break off. Lots of PB blaster can help too. Just to check, you got the forward nut on the leading edge, visible nut under the back and another nut under the zinc trim tad. Also if original drive shaft, it is carbon steel and so could have rusted and stuck in the crank splines (hopefully this is not the problem!).

Good luck!

Re: 1969 20 hp merc lower unit removal

Thanks for the info I did manage to get the lower unit off, there was a set screw on a collar on the shift rod when I loosened the set screw the lower unit slid off. I think I have bigger problems I took the prop off and the internal spline nut off and the casting behind the nut that holds the bearing on the prop shaft is cracked. I don't know if this unit froze or what but I think I will be needing some more parts.