Merc 15hp outboard - bearing carrier stuck - lower unit won't drop

craigswardmtbcraigswardmtb Mystic, CTMember Posts: 1,015 ✭✭✭

I recently bought a new to me dinghy and a low hour 2005 Merc 15hp 2 stroke outdrive. It also appears the previous owner did little to no maintenance. I discovered the prop shaft seals were leaking so I'm trying to replace them and running into challenges.  I'm trying to remove the bearing carrier with the appropriate merc tool (reverse threaded) and that darn thing won't budge.  I have it soaking in PB Blaster now and may have to try heat. Any recommendations on removal?

Right now I left the lower unit attached but my manual shows removing it.  I think it only shows removing it because it is showing how to do a complete tear down of the lower unit.  So my question is there any reason to remove the lower unit to simply replace the prop shaft seals?  Before I really apply the elbow grease I want to make sure I'm not going to break something internal because I should have removed the whole lower unit.

Post edited by craigswardmtb on


  • craigswardmtbcraigswardmtb Mystic, CTMember Posts: 1,015 ✭✭✭
    Well I decided to try and drop the lower unit. Put it in forward gear, disconnected shifter linkage, and removed the three bolts fastening the lower unit. The darn thing won't drop. I'm thinking there is corrosion in there. It separates at the front part of the joint but not towards the back where the drive shaft is. I was able to get a bunch of PB Blaster in the joint and bolt holes. So I sit and let it soak while I cuss out the previous owner....  I'm guessing he never dropped the lower unit.  40 hours on the motor but it's a 2005 and was operated in salt. 
  • AlswaggAlswagg Member Posts: 2,821 ✭✭✭✭✭
    Did you heat up the carrier and housing? Propane torch does a good job. You have to replace the O ring anyway plus the shaft seals.  
  • Michael TMichael T Member Posts: 7,009 ✭✭✭✭✭
    .....put the heat to the housing first to make it expand faster than the carrier, that should gas fumes nearby, right? At 20:1 you will be airborne!
  • craigswardmtbcraigswardmtb Mystic, CTMember Posts: 1,015 ✭✭✭

    Well I got the drive to drop after getting some wedges between the upper and lower.  There was a little corrosion on part of the drive shaft which was creating the issue.  The previous owner definitely did not ever change the impeller.  I replaced it and all seals.  I'm hoping this was the source of the water intrusion into the gearcase.  The oil seals on the lower half of the water pump were pretty buggered up. 

    I'm going to test and if it was than i'll leave the prop shaft seals alone.  Which would be ideal because I still cannot get that bearing carrier out...

  • Michael TMichael T Member Posts: 7,009 ✭✭✭✭✭
    ......if you have that housing separated would it be worth taking to a Mercury certified shop to have it serviced - to have the bearing carrier removed and prop shaft seals done?
  • craigswardmtbcraigswardmtb Mystic, CTMember Posts: 1,015 ✭✭✭
    It would but I enjoy the frustrations of servicing my drives. Plus everyone is so backed up with work right now. It would be weeks. It's typically an easy job if the carrier isn't frozen. 
    Hopefully my frustrations and problem solving helps someone else. 
  • craigswardmtbcraigswardmtb Mystic, CTMember Posts: 1,015 ✭✭✭
    Forgot to mention that the previous owner caulked around the water pump. Yes good Ole silicon. 
  • Michael TMichael T Member Posts: 7,009 ✭✭✭✭✭
  • craigswardmtbcraigswardmtb Mystic, CTMember Posts: 1,015 ✭✭✭
    A good amount of heat and a big breaker bar and the bearing carrier finally let loose. All seals are replaced on the lower unit now so hopefully my issues are resolved. 
    Moral of the story, dinghy motors need love to. Drop the drive once a season and grease things up. 
  • Michael TMichael T Member Posts: 7,009 ✭✭✭✭✭
    .....always I mentioned above -  heat, carefully applied, works wonders! Agree that a planned maintenance schedule always pays off!
  • brett12brett12 Member Posts: 1
    Hey mate im having the same troubles with mine but im unsure where to apply the heat.
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