1990 Mercury 25 hp upper drive shaft seals

fishpoo

Seaman Apprentice
Joined
Nov 7, 2016
Messages
34
Hello,
I'm trying to change the upper oil seals on the drive because their pretty chewed up...There looks to be two. I'm looking at the service manual and the instructions aren't really clear. Can I assume you have to remove the prop shaft to remove the drive shaft to get these out? Any tips would be appreciated
Thanks.

Model # 1025311JD
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Yes, the 2 seals under the water pump can only be removed and replaced with the drive shaft out, and that means removing the pinion gear screw (in the end of the driveshaft). And to do that you need to remove the propeller shaft.

The prop thrust hub is the tool to remove the carrier. Just pull the prop off and flip the thrust hub over. It will now engage with the carrier and you can put the prop back on and unthreaed the carrier. Just be careful, the carrier is left hand threaded... Once you unscrew the carrier, pull it and the prop shaft out. Also be aware the shift cam follower is loose, it may fall out of the end of the propshaft... Once you have the propshaft out you can deal with the screw in the end of the drivehshaft....

HTH,

Chris........
 

fishpoo

Seaman Apprentice
Joined
Nov 7, 2016
Messages
34
Thanks for the reply. So now I'm this far and it's winter in Jersey....lol..is it worthwhile to just put new seals in the lower?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
There's only the bearing carrier 'O' ring and the propshaft seals (aside from the driveshaft seals you are going to do anyway), so yes, I would....

Chris......
 
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