Mercury lower unit rebuild

[Jesse00721]

Sorry, could not find a specific section on rebuilding lower units. I have 1 that has a 20" shaft that I want to put a 25" shaft in. I know how to get the carrier assy out and have done it already, prop shaft I can't seem to figure out the pin / spring design to remove. I could get the drive shaft out without removing the prop shaft but my issue is the pinion bearing at the bottom drops out all 20 or so of those needle bearings. How in the world are you supposed to get them back in when u barely have enough room to look down the shaft opening. Does the pinion bearing have to be replaced everytime? I attached the bearing in question. Does the outside race get pushed in on the shaft as one assy? Does it come out the top or at the prop shaft? Is it pressed in? How do you get the old race out. A bit confused and manuals have been no help so if someone can give me the info needed that would be great. Weather you can explain in detail, pics or if there is a good video out there it would be appreciated. Thanks. Jesse

 

[schematic]

Re: Mercury lower unit rebuild

Haven't got a clue as to what model you are working on but usually that style of needle bearing doesn't always spill its needles. If it does you can simply reinstall them using grease to hold them intact. Make sure you find them all. The factory manual will give explicit instructions on how to drive the bearing out and pull in a new one. I can't guess on your model and gearcase so need serial number.....

 

[Faztbullet]

Re: Mercury lower unit rebuild

Sounds like a V-6 unit and prop shaft very easy to remove , just remove shift shaft. Reinstall bearings with light coat of transmission assembly grease or Vaseoline. Install the driveshaft to hold bearings in place and reinstall prop shaft then pinion. You will need the special tools, indicators and shims to set the pinion drive height or gears will fail. You cannot just swap shaft do to machining and manufacturing tolerances for factory.

 

[Jesse00721]

Re: Mercury lower unit rebuild

Yup, its seems the all these v6 models. Shift shaft just has to be removed? I pulled it from one but thought that was still stuck. Actually not sure it the case that was not beat to all hell if I could pull the shaft since I think it's like a "c" shape design. Ill take a look in a bit and double check that though. As for the serial number who knows. All these 80, 90 and at least rarely 2000 v6 lowers all look the same. I was trying grease the one time but that was not happening with the prop shaft in the way unless I was about 3" tall and could walk right into the lower unit��. Thanks for the responses. I'll check the shift shast again

 

[Jesse00721]

Re: Mercury lower unit rebuild

The one we took apart by smashing the casing cause it was toast did not come out when the shift rod was pulled. It only cam out when pins were pulled from the clutch dog or something like that, can't remember. I can pull the shift rod out of the other one tomorrow and see I'd f the prop shaft will pull out.

 

[Jesse00721]

Re: Mercury lower unit rebuild

Just a follow up that removing the shift shaft did work. I noticed between different v6 some are designed different but fortunately this one was removed by the shift shaft. Thatks for the input. All together and works great. Thanks again