Mercruiser Alpha One leaking gear oil from prop

[Gunn]

I noticed a small oil slick behind my boat last weekend when I put it in the water, from up on the lift. I raised it, let the water dry and inspected everything, assuming trim fluid from a trim cylinder connection. All dry. Then I noticed gear oil leaking off the lower skeg. Looking inside the propeller, I could see some wetness...

So I took off the propeller and anode. It looks like the prop shaft is dry and clean. However, I did find an oil and water mixture sitting in a small pool, directly behind the prop in a cavity (see attached image). You can see a bit of it in front of that circular ridge, but there is plenty more behind it.

So...what could be leaking behind the prop? Where are the next logical/possible areas to look for? It's been a couple of years since I've had the unit removed from the boat, so its nothing I've done recently...

Thanks,

 

[dlvwill]

down in exhaust cavity would be the bearing carrier o-ring leaking...normally it's prop shaft seal, are you sure it just didn't run back down in there when you had it tilted up?

 

[BillK2632]

I would suspect the oil seal carrier (cone shaped thing under the water pump) or the shift shaft seal. Both of those are easy to diagnose and fix - easier than the prop shaft seal.

 

[Gunn]

Thanks guys, so we have as possibilities:

• Bearing carrier o-ring
  
• Oil seal carrier
• Shift shaft seal

I'll research each one and see what I figure out. I'm pretty sure it's not the prop shaft. It was dry and I leave the drive down, and haven't really raised it much for awhile.

Thanks,

Tom