Leaking Gear OIl from Prop

[chrisreyn]

OK, so I have read all the various threads about unburnt gas/oil leaking from the prop, however my leak is 100% definitely gear oil.
Honey Mustard colored and smells of gear lube. Obviously has water in it and I have oil stains coming from the pee holes at the upper end of the LU.
I changed the LU lube last week, and changed the gear lube on 8/31 and there was no leak at that time.
Checked behind the prop and can see no monofiliment anything obvious.

What all is involved with changing out a prop seal? I am fairly mechanically inclined, but have never opened an outboard before... on a scale of 1-10 how difficult is replacing the lower unit seals, and I guess I should replace the impeller while Im in there?.
Oh, its an 85EL77S.. 1977 85 HP ..

 

[cdn-pk]

Re: Leaking Gear OIl from Prop

if there was no leak a week ago, i'd look closer at the fill/drain plug seals. did you change the nylon washers? (or do you have a rubber o ring). and if you take the gearcase to a dealer they can pressure test it and see where the leak is....

anyway just my thoughts, i'd hate to change a seal and not fix the problem.

 

[hidef]

Re: Leaking Gear OIl from Prop

Upper drain holes in the lower unit are draining unburnt oil and gas from the engine. Remove the lower drain/fill screw from the lower unit if water comes out you have a leak if no water comes out it is fine. Oil coming out of the prop is generally from the exhaust and it is very easy to confuse it with lower unit oil.

 

[chrisreyn]

Re: Leaking Gear OIl from Prop

Im certain it is gear lube, Ive seen the unburnt oil/gas back when I decarbed the engine and this is totally different. It wasn't leaking from the drain holes, but rather surprised me by pouring out a cup or two's worth when I lowered the engine from a tilted position. ..
I am trying to decide if this is a job I should tackle by myself without help,( no experience with outboards), or something I should take to a shop..

 

[boobie]

Re: Leaking Gear OIl from Prop

Take it to a shop and have it pressue and vacuumed checked. Will take all the guess work out of where it's leaking.