Yamaha outboard oil in exhaust water

[dial_amonkey]

G'day

Yesterday when running my outboard in a bucket I noticed quite a lot of blackened oil on the bucket edge .. there was also some white smoke when I revved hard.

The engine starts and runs well, compression seems normal, the oil in the engine is clean - not milky, I know the fuel mix is a little too rich., but i replaced seals in the carb recently ( and it needs adjusting)

I'm at a loss of how to identify the source of the oil - a seal or the rings? or something else.?

Can anyone give advice or steps for identifying how oil is getting into the exhaust water?

Many thanks for any advice or any input on how to approach this, It's very much appreciated..

[a64pilot]

4 stroke?
If so don’t do anything until you take it out and run it decently hard for awhile. If after that it still continues but runs smoothly do a compression test.
Plugs can also tell a lot. You sure it’s rich? Did you re-jet it to get it rich?

[billknny]

Are you sure your black sludge isn’t just soot from partially burned fuel??? That would be typical of running “rich”.

[a64pilot]

Originally Posted by billknny

Are you sure your black sludge isn’t just soot from partially burned fuel??? That would be typical of running “rich”.

That is what I am thinking, and you can only adjust the idle circuit, main circuit you have to re-jet, plus if he takes it out and runs it and the black oil disappears that sort of proves it’s fuel oil carbon mix.
I assume it’s been run a bit in a bucket or hose and if so that’s sort of normal.
High carb float level can make one rich too of course.

[dial_amonkey]

Thanks for the advice! .... ...Ahh Yes 4-stroke - I should have mentioned that

- And Yes: I adjusted the float valve - because the carb was over flooding - it's tricky to get it right but is now is OK.

- Rich fuel mix – well I know the sound the engine makes when the choke is accidentally on and the engine struggled a tiny bit like that – so I presumed (in error?) perhaps the mix was a bit rich.

- Carb: The idle circuit – There is a "Pilot Jet" which in some service manuals shows a "Bushing" blocking the tube and in other manuals no bushing – I’m not sure what this jet does: But at some point I ( experimentally) blocked the tube with a grub screw and the engine worked perfectly – so I left it like that until just recently – might put it back.

The spark plug was black sooty - not so much oily - But I need to confirm.

The Sludge was definitely oil it felt clingy and slimy like engine oil does.

OK lots of good advice, if it's still hemorrhaging oil after a long hard run, i try an compression test - well - I have a leak down tester.

Cheers
- Matt