1998 johnson 115 lower unit leak

[Lewist2]

Have a 98 johnson 115. Noticed gear oil slowly running down the foot right behind the prop. Pulled the bearing housing and replaced the prop shaft seal and the o ring on the other end of the housing. Cannot get the o ring to seal. Taken it off multiple times and just keeps leaking. Any thoughts?

 

[saltchuckmatt]

Have a 98 johnson 115. Noticed gear oil slowly running down the foot right behind the prop. Pulled the bearing housing and replaced the prop shaft seal and the o ring on the other end of the housing. Cannot get the o ring to seal. Taken it off multiple times and just keeps leaking. Any thoughts?

Prop shaft might be scored? Dealer usually does a pressure test even though one guy told me the true way is a vacuum test. Could you be confused with just a rich running outboard with dripping down through the exhaust? Usually if there is a leak you will get water in with the oil.

 

[Lewist2]

Prop shaft might be scored? Dealer usually does a pressure test even though one guy told me the true way is a vacuum test. Could you be confused with just a rich running outboard with dripping down through the exhaust? Usually if there is a leak you will get water in with the oil.

It’s definitely gear oil coming out.

 

[Lewist2]

It’s definitely gear oil coming out. Drained the foot and replaced everything. Brand new gear oil is leaking out. Coming from inside the foot on the other end of the bearing housing where the o ring is

 

[Chris1956]

The only reasons the gear oil would leak with new seals is if the bearings allow prop shaft movement that the seal cannot cover, a nick in the propshaft, bearing carrier or housing ripped the Oring or seal or the housing is out of round, or scored.


You are only supposed to put grease on the seals and orings. You could probably get away with permatex #3 aviation sealant on the orings. That may help.

 

[racerone]

Do a pressure test on it.

 

[McGR]

How's the inner surface of the l/u housing. Maybe there is sand/debris in there. Maybe give it a good cleaning, grease it up and try again?