Lower Unit leak

[Metatron]

Howdy!
I'm relatively new to boating so please bear with me. I've been searching around the forums (great place here!) and just want to post my particular problem as I've seen variations of it.

Not long after trailer the boat home last weekend I noticed something leaking out of one of the holes of the lower unit. Can anyone tell me if I've got a bad seal or if something else may cause a small leak? I've attached a pic with an arrow pointing to the hole where the oil was coming out. It's not a continuous leak, it's essentially stopped now but I'm still leary. The fluid looked a little milky (I know, sure signs of water) but it's consistency felt pretty close to that of new gear oil. I opened the drain plug and it's more of the same slightly milky oil. What are your thoughts? I'm fairly certain I should have it tended to before I take it out again but who knows...that's why I'm here

Thanks for the help!
M

 

[emckelvy]

Re: Lower Unit leak

That hole is just a drain for the cavity at the top front of the gearcase. This is in the general area of the shift shaft.

You may have a leaking shift shaft oil seal but it's also possible the oil seals under the water pump could be leaking. Since your gear oil is milky you've definitely got signs of water intrusion.

You'll need to pull the lower unit and check for obvious signs of external leakage. If you don't see that, the water pump will have to come apart so you can inspect the (2) oil seals pressed into the lower pump body.

Check out a parts breakdown for your motor here:

http://www.mercruiserparts.com/SelectModelType3.asp?class_id=2

Meanwhile, if you need to run the motor before you tear into it, drain and refill with fresh oil. If you're running in salt water, use a marine-grade gear oil. If you're in fresh water, you could get away with using inexpensive 90W automotive gear oil as long as you keep an eye on the oil quality, or change it every time you go out (if it's leaking that badly).

HTH............ed