Oil leak around propeller hub

[bstig60]

I have noticed a small amount of oil leaking out the hub of the exhaust. There appear to be two oil seals there, a nut and a tab washer. Can the nut be loose or should I replace both seals? Seal Part numbers 69188 and 69189.

 

[flyingscott]

Time for the smell test. Does it smell like fuel or gear lube if it smells like fuel probably normal.

 

[fhhuber]

Yep... depends on the source of the oil as to what you do.

Exactly what engine?

If its a 2-stroke some oil there is normal. just unburned oil from the gas/oil mix or the oil injection. (we hope)

Do an oil change on the lower end. If you get water out of the gearbox then you have a problem.

 

[sam am I]

It's probably gear oil.............fishing line eats those seals usually!!! I bet you'll find some wound around the prop shaft when ya tear it down. I just took my LU off for seal checks and a pressure test and I had a ton of line spun on.......Hope I can re-use it


https://www.youtube.com/watch?v=HRpfaOiXxWo


This might help.......although he is a little heavy handed with a **hammer/ improper tools IMO**

Sure.......so moving on then

Anyway, his details/cinematography are pretty good and ya might use this as a "guide" / "reference" to replace those seals if need be

**Side rant......

(He breaks out a chunk the bearing carrier casting end @ 10:30 by prying out stubborn seals incorrectly.........this is NOT how to treat the owner's properly and SOME mech's do this crap all the time which fries my bread cuz it is hidden when assembled. Although not critical, it's going to potentially catch and hold more line/crap easier and he should have replaced what he broke at HIS cost IMO)........Benefit of the doubt? Maybe he replaced it and didn't show us that part?

Had a Honda mech once tell my GF she needed a "oil pan update" after he stripped out the threads on the drained plug......un huh, That CLASSIC lives on even to today in the fam.

 

[bstig60]

Yep... depends on the source of the oil as to what you do.

Exactly what engine?

If its a 2-stroke some oil there is normal. just unburned oil from the gas/oil mix or the oil injection. (we hope)

Do an oil change on the lower end. If you get water out of the gearbox then you have a problem.

The engine is a 1988 Mercury Classic Fifty 45hp.

 

[fhhuber]

Do the cheap check first (you have to do it anyway if changing the seal)

Drain the gear oil. If its got water you need seal(s)... if not you are most likely looking at unburned 2 stroke oil.

Good idea to do an annual gear oil change anyway. You get to see if there's abnormal amounts of metal chips or water in the oil.

A bit of "fuzz" on the magnet (which is part of the drain plug) isn't a problem. You get some normal wear of the gears. chunks is bad.

 

[bstig60]

I pulled the prop off again and there is not sign of any fishing line. The oil there appears to be coming out of the out of the exhaust and not from around the seal. I am going to change the gear oil anyway when the weather clears up a bit.

 

[flyingscott]

Cheapest is the smell test. Gear lube has a very distinctive smell. Don't get caught up on having to take a lower unit apart on assumptions. And before you take the lower apart an an assumption have a pressure and vacuum test done. If you had seen the amount of lower units people tell me need to be resealed ,only to find out they forgot to put the seal back on the drain screw it would amaze you. Water in the lower does not necessarily mean new seals.

 

[sam am I]

I pulled the prop off again and there is not sign of any fishing line. The oil there appears to be coming out of the out of the exhaust and not from around the seal. I am going to change the gear oil anyway when the weather clears up a bit.

Agree with f.scott, my garage smells to high heaven right now with the gear box open............My concern/guess not looking at, is the "oil" in exhaust? Really shouldn't be liquid oil there, perhaps thick'ish carbon but not "dripping oil" unless you have bigger issues in the engine.

Not to push the gear oil and if the shaft seals are good but it is smelly gear oil, don't rule out the rear o-ring at the back of carrier isn't leaking....GL

 

[flyingscott]

This is what my lower unit looks like on my 2 hp after winterizing oil in the exhaust is normal my lower unit is tight. I would be more worried if there was no oil in your exhaust. All my motors look like this if I go out there right now most of my motors will have drops of oil under them.

 

[fhhuber]

Yep.. All of my 2-strokes, from .020 ci to 150 hp drip at least a little oil from the fuel/oil mix.

Sure, you can mix exactly and have practically no oil in the exhaust. But that leaves ZERO spare protection in case of high load.

I'd rather replace the plugs a little more often than need a rebuild.