oil leak around prop

[vk355a]

Hi guys, just got a boat on saturday or seemed fine until today, i found oil leaking from prop area.

The motor is a 40 evinrude, not sure on age but would have to be 20 years old. Im assuming there is a seal behind the prop that is leaking. Took the prop off, there are 4 bolts in behind the prop would they be the ones to undo to get to the seal, or are there others as well. The oil looked blacky grey colour. Any help would be great.

Bretto.

[FNQCairns]

Most probably used 2 stroke oil finding it's way down and out, not a problem, it's thin and smells of engine:), gearbox oil will be slippery-er and have a more synthetic type of smell, acrid even.

cheers fnq

[tunaticer]

Generally as FNQ suggested it most likely is two stroke oil mixed with oily carbon deposits in the exhaust. If the oil patch is dark coloured and acrid smelling it is a 95% chance it is two stroke oil, I am yet to see a dark coloured gearbox oil that dark...its possible but I am yet to see it.
If however the oil looks creamy it will be hyrolysed gear oil (water mixed) indicating a seal has let go in the gearbox somewhere.

[BaitThrower]

Sounds like unburnt oil and carbon to me. My old Johnson 15hp did that on occassion. Nothing to worry about.

[BM]

Bretto,

As mentioned above its most likely 2 stroke oil and of no concern.

To reassure yourself crack the drain screw at the bottom of the gearbox (at top of the skeg but below the gearcase bulge) and let a little oil out.

If the gearbox oil is milky then you have an issue there also. If the colour matches whats come from the prop (very unlikely) then it would be a gearbox leak. This would however be evident to some degree when removing the prop.

Oil would be evident around the propshaft seal whereas 2 stroke oil that washes out of the system wont normally be around the propshaft seal and more commonly running along the bottom of the gearcase cavity.

Cheers

[ronnien]

hi all,
mate i hope it is like everyone is saying.
the first service i had done on my 40hp merc (not new), they found that my gearbox was milky & wanted me to replace the seals, no worries. this is where it went to shit, when they were doing the seals they cracked the bearing carrier.
after the service it leaked oil from in behind the prop, after taking it back 5 times they kept telling me that it is unburnt oil & that this model ran dirty anyways.
but i never seen it do that before i had the service?
so getting worried i ph another outboard mech, after five minutes with a torch he found the crack in the bearing carrier. cost $350.

for peace of mind go & get it checked out... you dont want to be out & it fails & stops.

ron.

[vk355a]

Thanks heaps guys, the oil dose smell like 2 stroke.
Theres no oil leak there this morning so fingers crossed.
When we flushed the motor sunday it was very smokey maybe to much oil getting in to motor whilst flushing it.
I did have the choke on when flushing, trying to bring the revs up a bit. Next flush i might just let it idle & see what happens.