Is this unburned fuel/oil or something more?

  • KG25
    Lakeville, MN
    Posts: 52
    April 26, 2014 at 4:01 pm #1355707

    I ran my outboard on muffs today at idle and got this around the prop and through the prop also. It is a ’95 mercury 40hp 2 stroke 4 cylinder. I bought it over the winter. I have gotten this milky gray sludge on my previous smaller outboard but this seemed like a lot. Is this just unburned 2 stroke oil and gas or do I have other issues or some kind leak?

    It seemed to idle just fine. I changed the lower unit lube earlier this spring and it didn’t appear to be milky or have any water in it.

    Thanks for any insight!

    Tom Sawvell
    Inactive
    Posts: 9559
    April 26, 2014 at 4:11 pm #1406430

    Did you foam the engine when you put it away last fall? Could be from that.

    brad-o
    Mankato
    Posts: 410
    April 26, 2014 at 4:18 pm #1406431

    It looks like penetrating lube. Maybe they did not want to take the prop off to lubercat so they just spayed penetrating lube

    Sean Reames
    Posts: 61
    April 26, 2014 at 4:55 pm #1406433

    More than likely if the engine was winterized properly that is just the fogging oil that the engine didn’t burn. it is just getting rinsed out of the motor.

    KG25
    Lakeville, MN
    Posts: 52
    April 26, 2014 at 4:59 pm #1406434

    Thanks guys. The previous owner said he fogged it but I am just taking his word for it. Being a 4 cylinder vs my previous 2 cylinder I guess logically there would be more residue also. But I could be wrong. I just wanted to make sure this isn’t a sure sign of some other issue before I take it to a lake for the first time.

    dorancehefte
    Wisconsin
    Posts: 155
    April 26, 2014 at 6:12 pm #1406440

    It looks like water/grease from your lower unit. The mixture turns milky like that when water leaks thru the seal It’s simple to check and may save you some serious trouble.

    KG25
    Lakeville, MN
    Posts: 52
    April 26, 2014 at 6:21 pm #1406444

    Quote:

    It looks like water/grease from your lower unit. The mixture turns milky like that when water leaks thru the seal It’s simple to check and may save you some serious trouble.

    Thanks. Do you mean simple in just checking the lower gear lube for water or something else? I can drain some out to see what it looks like.

    396ranger
    Cottage Grove MN
    Posts: 283
    April 26, 2014 at 6:24 pm #1406445

    Change your lower unit oil to be safe. On a new to you outboard it would be a good idea, oil is cheep and a little stinky but it will atleast give you a starting point.

    KG25
    Lakeville, MN
    Posts: 52
    April 26, 2014 at 6:28 pm #1406446

    Quote:

    Change your lower unit oil to be safe. On a new to you outboard it would be a good idea, oil is cheep and a little stinky but it will atleast give you a starting point.

    Thanks, I did do that a couple of weeks ago. The old oil was inky black but I didn’t see any signs of water. I used quicksilver lower gear lube to replace it.

    milemark_714
    Posts: 1287
    April 27, 2014 at 9:25 pm #1406634

    It is just exhaust goo from unburned lube/fogging oil.Very common with that motor.Leave it vertical for a week,and you will see it drip out.Sounds like your gear case is good with the dark oil,milkshake looking oil is not good.

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