Lower Unit oil leak

[duckinit]

Once again I am back to ask the experts a question. I have a 1977 model 200, Mercury 20Hp motor and I recently replaced the entire water pump myself with the help of this site and my trusty Seloc repair manual. I have just run the motor out of water with water muffs and it is spitting like a champ. One problem though - I have left it set for about 2 weeks since I ran it and when I went to check everything out before an adventure that I am hoping to take this week. I have a small - very small puddle of oil at the base of the motor on the ground. It appears that it came out by the prop. I am dropping the lower unit tomorrow and gonna check all the seals on the water pump and make sure that they still appear to be tight and not leaking. Any suggestions? Thanks in advance to all that help out on this site. You all are champs.

 

[rabidfish]

Re: Lower Unit oil leak

It's common for unburned fuel/oil to puddle under the engine. Just check the level of the lower unit. If it is OK then don't worry about it.

 

[dka1ser]

Re: Lower Unit oil leak

What color is it? My outboard (115 I-6) will leak for a few days a *black* mixture of unburnt oil and gas out the bottom of the prop, stinking up my garage. <br /><br />However the gear oil is brown or milky depending on if its got water in it. I wouldn't worry about it if its really thick and black, as that's just the engine. <br /><br />- Dennis

 

[duckinit]

Re: Lower Unit oil leak

It appears to be gear oil. It is brownish and slick like gear oil.

 

[dka1ser]

Re: Lower Unit oil leak

Replacing the water pump, unless you dropped the lower unit shouldn't have disturbed the seals too much. I agree with Rabidfish, keep checking on the level of the lower unit oil and unless it starts dropping or getting milky as if water is mixing in with it don't worry. <br /><br />However, I still would want to believe that its unburnt oil/fuel. I always have MUCH more leaky oil/fuel mess when I run on the muffs as opposed to a day at the lake. <br /><br />Just keep an eye on the gear fluid, and enjoy.

 

[andrewkafp]

Re: Lower Unit oil leak

What does it smell like? Gear oil has a distinctive pungeant smell(Like SAE 90 grade diff oil). If is smells like fuel, it's only unburnt 2 stroke which is common in motors that sit for a while.

 

[KCLOST]

Re: Lower Unit oil leak

Where is the oil dripping from the lower unit? Is it coming from underneath the prop or through it?

 

[duckinit]

Re: Lower Unit oil leak

It is coming from under the prop.

 

[KCLOST]

Re: Lower Unit oil leak

Ok, since you say it is brown in color that most likely is lower unit lube... Not a good sign...<br /><br />If I were you I'd perform a pressure test on the gear case and determine where the leak is coming from, (most likely the propshaft seal) and go from there...<br /><br />If that is what it is, it should be fixed before next season. You don't want water in there and damaging the vitals...