1978 80hp Dropping lower unit to kill the oil/water leak

[SEABEE#2]

Hello. I just dropped the lower unit, but am wondering where the best place to buy a seal kit is? OR just the individual seals. Thanks!

 

[Prophammer]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

if you can't find it here(iboats) ishopmarine.com has stuff like that and NAPA has a full line of marine parts

 

[SEABEE#2]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

I have found the leak at the shift shaft. So far, I have disassembled part(s) numbered from 43-46 on the IBOATS site...

My question is, Do I need to remove part #42 which is the bushing assembly to get to #41, the O-Ring, or will replacing part #43, the oil seal fix it? (It is leaking through the bushing assy as.)
If so, How do I remove the bushing assy.?

Thanks!

 

[Moody Blue]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

Can't make out any details on the diagram you included. The shift shaft bushing can be bought as a complete assembly - just remove the old and install the new. It is complete with new seals and o-ring. There is a "special" Merc tool for removing the bushing but with a bit of creativity you can make your own tool. The bushing has two slots across the top face where the "tool" drops into. The entire bushing unscrews like a big bolt, up and off the shift shaft. It won't come out easily, especially if its been there since '78.

Be carefull when removing the bushing NOT to pull UP on the shift shaft. If you do, you will disengage the shift cam located down in the lower unit. A real PITA to get it back together.

 

[SEABEE#2]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

Good to know. Is there a name to this special tool so I can get an idea of what I have to copy or make?

Thanks for your info!

 

[Moody Blue]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

Here you go.

Shift shaft bushing assy Shift Shaft Bushing with Seal for Mercruiser R Mr Alpha One and Gen II 30617A2 | eBay

and tool Mercruiser Shift Shaft Bushing Installer and Remover Special Tool 91 31107T | eBay

Pretty sure that the same bushing is used in all Merc units, but check p/n's to be sure.

 

[SEABEE#2]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

Thanks for your time and input!

 

[SEABEE#2]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

Unfortunately, The bushing did not come out without the shift shaft. The shift shaft as well as the bushing had some burrs from what appears to have been someone else working on it. How do I put it back properly into the shift cam? So far, I wet- sanded the burrs on the shift shaft and placed it into what looked to be a little washer/nut that was sliding around. Is there more to it or is that all thats required to properly assemble it? Thanks!

 

[SEABEE#2]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

Anyone know how to properly relocate the shift shaft after totally removing it?

 

[Moody Blue]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

Located on the shift shaft just below where the bushing sits there is a groove. An "E" ring clips into this groove and prevent the shaft from pulling up through the bushing. Do you still have the "E" clip or did it drop down into the lower unit?

The region where the shift shaft passes through the bushing seal must be free of any nicks or gouges or it will not seal properly.

There is a really good write up in this forum ( by chris1956 I think) describing how to reinstall the shift shaft if accidentally removed. Use the search feature and try to locate it. At the splined end of the shift shaft in the lower unit is a shift cam with a splined hole. The shift cam simply slides onto the splined shift shaft. It is captured top and bottom between two flanges in the lower unit and is free to rotate and slide around between the two flanges. The trick is to get the shift cam back into the right position directly below the shift shaft so that you can re-engage the shift shaft.

 

[SEABEE#2]

Re: 1978 80hp Dropping lower unit to kill the oil/water leak

I have the "E": ring clip still. Ok thanks! I will try to locate this forum.