Black substance is coming out of the hub

[JTMaclain]

I have a 1998 30hp 2-stroke Johnson motor and there seems to be a black substance that comes out in between the prop and the lower unit. I have already changed the lower unit oil and it looked just fine. The black stuff feels like oil but I don't know where it could be coming from. I was wondering if this is normal or if is isn't what is it and how do I fix it?

 

[ezeke]

Re: Black substance is coming out of the hub

That is most likely excess oil that wasn't burned in combustion. If you run the boat slowly at the end of your trip, it will tend to increase.

 

[Duck Loads]

Re: Black substance is coming out of the hub

I get that kind of gunk when I run my GT 150 on the muffs. It freeked me out at first, but I have learned to ignore it.<br /><br />Be safe,<br />Duck L.

 

[JTMaclain]

Re: Black substance is coming out of the hub

There seems to be alot of the black stuff, if it is exess oil I don't see how there could be that much. Can someone give me some more details or another reason for the black stuff.<br />Thanks

 

[OBJ]

Re: Black substance is coming out of the hub

JT....not all the oil ya' mix gets burned in the combustion process and gets blowed out the exhaust. It collects on the exhaust cavity and when you park the boat, gavity takes over and out she comes.<br /><br />If it's in excess, check your mix. You should be running 50:1. Increasing the mix will only aggrevate the problem.<br /><br />When was your last tune up? Poor combustion is another cause. Not only does the gas milage go up, but the stain on the garage floor gets bigger. <br /><br />Keep us posted....thanks.

 

[alcan]

Re: Black substance is coming out of the hub

Ok, since you want something to worry about, try this. Maybe you have a carb float valve not closing. This might cause a cyl or two to run a little on the rich side. Or maybe you got a plug that is not firing and all the unburned fuel is washing all sooty residue out of the exhaust. Check it out, you may have a problem. Unfortunatly we can't see the floor under your motor, so it's hard to say for sure. I will say that a six to eight inch drip stain under the exhaust is fairly normal for a 2-stroke. A drip stain will be black and nasty looking. If the oil looks like honey (clean) you got a problem.

 

[JTMaclain]

Re: Black substance is coming out of the hub

Thanks, I think from everyone's observation that it is just a little exess oil. The drain spot is less than 6 inch's. I just wanted to make sure, once again thank you everyone and I will let you know if it is something else.

 

[Cricket Too]

Re: Black substance is coming out of the hub

What a coincidence, I just came back in, parked the boat in the driveway, ate dinner and went back out and noticed the same thing. I thought I was dealing with a lower unit seal and was just about to put a post up about it when I saw this. My spot is about 3-4 inches, black and nasty looking, smells like exhaust and feels like a thick oil, also smells a little like gear oil, but nowhere near as strong and nasty. I'm still gonna look at my lower unit oil but I think it's just excess, unburned oil as per the description on the post. Thanks, Mike.