Lower Unit Bearing Carrier Leaking

tfowler111

Cadet
Joined
Aug 13, 2024
Messages
6
Lower unit was leaking gear oil, area forward of prop and bearing carrier locknut in exhaust passage was filled with gear oil. Would not hold any pressure with hand vacuum pump. Put ~10psi in through fill hole and had large bubbles coming from around edge of bearing carrier. Some tiny bubbles from prop shaft seal so I do not think it was main leak. Is it worth it to attempt to replace bearing carrier o-ring? Does anyone have success or is the lower cowling usually out of round or have damage that would prevent it from ever sealing.
Area in red was where large bubbles were coming from.
 

Nordin

Commander
Joined
Jun 12, 2010
Messages
2,555
If you can manage to remove the lock nut and the carrier without damage them..... yes it is worth it.
Change the o-ring and put some liquid gasket such as Permatex form a gasket aviation no.3 or equal at the o-ring.
I use this liquid gasket in many application on outboards.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,037
If you can't find the right tool?? Then the part is still available. You might cut it out(very carefully) then the carrier can be resealed.
Never heard of the case being "out of round" so I wouldn't worry about that.
Dis-assemble before you buy parts, Replace ALL the seals since it's apart.
Forcing air through the prop shaft seal, possible future failure???
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,818
Any chance that lower unit was full of water and froze ??-----Best to take lower unit apart for full inspection.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,818
I guess I missed your location in post #1-----Sorry to bother you !
 

tfowler111

Cadet
Joined
Aug 13, 2024
Messages
6
If you can't find the right tool?? Then the part is still available. You might cut it out(very carefully) then the carrier can be resealed.
Never heard of the case being "out of round" so I wouldn't worry about that.
Dis-assemble before you buy parts, Replace ALL the seals since it's apart.
Forcing air through the prop shaft seal, possible future failure???
Yes plan on now replacing o-ring and prop seals, see if it holds pressure then. If it doesn't take off lower and look at the seals on top of unit. Do you think 10psi is too high for this unit?
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,909
Actually, the service manual states 16-18 PSI for pressure testing and then followed by a vacuum test of 3-5 inches. So 10 psi is barely enough to detect the leaks.
 
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