OK, so here is what happened. About 20 minutes ago I hooked up my boat and pulled it to my house to pick up my fishing gear. As I am walking around my boat to load my rods and tackle, I look down at my lower unit and can't believe my eyes. There is oil dripping down both sides of the lower unit. I checked both screws and they are on tight. As I look a little more, I start to see that the oil is comming from where the prop and the lower unit meet. I have not used my boat in about 12 days. It has run flawlessly all year long so i'm stumped as to what happened and how the oil got out side the lower unit with out it even running. I noticed nothing out of the ordinary last outting. By the way, the motor is an '83 50hp Mercury

What do you guys think that could be wrong with it? Is there some type of seal that is between the lower unit and the prop. Could that have gone bad? Also, what am I looking at ($$$) to have it fixed?

Here are some pics to let you see what I am talking about.

The marker shows where the oil is comming from.

Yes there is a seal behind the prop.. First I would look at the oil in the L/U to see if water had gotten in there. take off the vent screw at the top of the L/U and slowly loosen your fill screw and look at the oil that comes out. If it is milky white you might as well take the L/U off and check for damage. if no water is present I would replace the seal behind the prop. But First get manual for your motor about 30 bucks or so. That will save you lots of money.. It has me, The best $30.00 I have ever spent. as a good manual will walk you though just about an engine rebuild. If you need a need to know where to get one email me at bamabower1@yahoo.com and I will get you a link when I get to my home puter.

Before getting too concerned, it may just be exhaust waste coming out.  Pull the prop off and look to see if it's coming from up inside the exhaust area of the LU or if it looks like it's coming down the bearing carrier for the prop shaft.   If coming from up inside, it's just exhaust waste and nothing to worry about.  If it looks like it coming down the bearing carrier check the oil level in the lower unit and also check for water.   First, trim the motor down to approx level and take the top plug out and see it any oil comes out, if it does, it should be black, chocolate or cream is bad news.  If none comes out, get you one of the pumps that screws into a quart of gear oil and has the hose end that crews into your LU .  This you can usually find for less than $15 at wally world.   Then pick up a quart of 85/90, 100% synthetic gear oil.  If you get the fosil based, you have to be sure to get some GL-5 rated, don't even try GL-1.   When you have these, put a small pan under the LU to catch anything that comes out and take the bottom plug out, let just a little drain out to check to see if it's water or black oil, then screw the pump hose end into the plug hole, now take the top plug out and pump oil into the LU.  It should only take a very small amount to make it start coming out the top, if it takes much, you probably have a $300 leak.

Thanks for the input so for guys!  I'm hoping that I don't have any real damage beacuse I have not run it since I have noticed the problem.

First, trim the motor down to approx level and take the top plug out and see it any oil comes out, if it does, it should be black, chocolate or cream is bad news.

Does chocolate or cream indicate that water has been present in it?

Yes, any color other than clear oil or black from dirty oil is bad.  Browns/creams is water mixed with the oil.

my mercury premium + lower lube is green.  my buddy had a evinrude with somekind of premix problem looked just like that.

did you by chance, have it running on a water hose since you last used it?

Pull the prop and see if by chance you have wrapped up some fishing line around the shaft, that will take the seal out fast. Wipe it out real good, top off the LU,  and put on some ear muffs (on the lower unit not your head), and run it, watching the seal area for leaks.

Posted by: JoshKeller Posted on: Today at 1:04am

did you by chance , have it running on a water hose since you last used it?

No, I have not run it with the hose since my last outing.  About 2 weeks ago was the last time that I have used it and I just pulled it out of the water and have not run it since.

Thanks for all the input guys.  What I think that I might do is take it back home this weekend to where I store it for the winter in my grandpa's heated warehouse.  So, with that being said, I might not get it fixed until next spring or so.  Would that be a problem having it sit like it is for 5 months or so without getting the seal fixed.  I really do not think anything is seriously wrong with the LU , it just sounds like a bad seal.  So I might just wait to get it fixed in the spring.  I'm pretty handy with tools and stuff but I might just let the mechanic handle this one.  I don't want to mess anything any worse.

The reason for storing it so early is that for one, I might have only one month left to fish (live in NE  > ) and second, with college and work I won't have too much time left this fall to fish.  

Let my know what you guys think.

You should check it for water before doing that.  You store it that long with water in it and it will be junk next spring.  One big rust block inside.

Having worked for the company that supplied Merc and OMC with their seals it looks to me like your seals are shot but check the other options noted first. The number 1 destroyer of seals in an outboard is fishline. The same goes for the seal in your trolling motor.

Your prop looks like it has been dinged a few times. If it is running to far out of balance that can also cause a seal leak and could cause some bearing damage.

Your prop looks like it has been dinged a few times. If it is running to far out of balance that can also cause a seal leak and could cause some bearing damage.

If it is true that the bearings are damaged how much can I expect to pay to have it fixed. Also, thanks for the heads up on the prop. I will pry go and get a new one. I have looked at them before. Is the only difference between stainless steel and a regular prop is how durable it is? Is it worth the extra money to put a SS prop on a 50hp motor?

If it does have water in the LU, should I just pump new oil into the LU?  Will that get all the water out or is there some type of "rinse" way that I should do to ensure that I get the water out (if its in there).  I already have the pump for the LU and have changed the oil at the begining of the year.

Thanks for all your help!!! It is truly appreciated!!

When my dad would put up the boat for winter,normally a couple weeks before hunting season,he'd always replace the oil in the lower unit,take out the bottom screw,drain the oil,take out the top plug

pump oil in the bottom hole until it came out the top hole,put the plug back in then the bottom plug.

Alright, I drained (and refilled) the LU oil and I did not see any water or metal shavings in oil.  The oil in the pic is not even close to the same color that came out of the LU.  The LU oil looked fairly new.  That is why I think it is not the same oil that is leaking down the side of the motor. I'm sure that the seal is shot, although I have not pulled the prop to see if it is though.

Is it possible that the oil/greese on the prop bearings got water in it causing it to run down the motor?

Has anyone has this type of problem before?

If the oil drained from you lower is the color of new oil and much different from the leaked oil I am at a loss. I don't know where the leaked oil is originating. I would haul to a good marine mechanic and ask his opinion. Don't assume neither your seals or bearings are shot.

Re your prop it probably can be repaired. A stainless prop will be more efficient so you can run at the same speed at lower rpms or have more top end speed. I changed my prop to stainless and kept the old rebuilt aluminum as a spare.

You don't say how big your motor is but from the picture I guess it is 90+. The damage to your prop looks more like sand or silt than rocks and stainless stands up very well to these. Rocks really do a number on both. My stainless is in for repair right now.

You might be able to find a good used stainless for a fraction of the cost of a new prop. Try and find a good prop guy or shop to help you with any selection. In MHO props are at least or more imporant to boat performance than tires are to cars and trucks.

Thanks for the help.  I think that i'm just gonna drop is off at the marine mech. shop and see what he thinks. Also thanks for the info about the props, it was very helpful!

You don't say how big your motor is but from the picture I guess it is 90+.

 

Its actually a 50 hp Merc.  I wish it was a 90.  That would really push my 17' aluminium bass tracker right along!  ;D