1987 Evinrude XP 150, Leaking black oil from midsection????

[joshua27]

I have a 1987 Evinrude XP150 motor that I recently picked up on a fish and ski boat that I bought. The motor runs great. I checked compression and while sitting cold the motor has 90PSI across all 6 pistons. I've since decarboned the motor with seafoam so I assume compression should be even higher.

My question is, what the hell is all this black oil leaking from under the outboard? It appears to be coming out right where the midsection joins the top portion of the outboard. I noticed it today. I assume it's excess unburnt oil but it's NOT leaking out of the propeller, just from the upper midsection area as best as I can tell.

Anybody got any ideas? The fuel I've put into the gas tank so far has been mixed 50:1. This motor previously had oil injection but was disabled at some point prior to my purchase. Anything I should look for? Maybe there is a lot of oil floating around the bottom of my fuel tank? Hell I don't know.

One thing I did notice with this motor is it runs a little on the smokey side. Not so much when it's opened up but while idling on muffs or at the dock, etc. it's smokey. I've owned an assortment of outboards over the years and this one seems to smoke more at idle. It's not obnoxiously smokey but it's enough to notice.

 

[Crosbyman]

maybe decarbing with seafoam loosed up a pile of previous carbon deposits along the exhaust route... such black goo... is surely carbon rich and will eventually stop leaking out.. just mho.. experts will add other options


If ok for your engine, ​running it on some XD-100 for a few tanks should help the decarbing further and reduce smoking.

 

[flyingscott]

That looks like what happens when the carbs drain and fuel runs out of the airbox. I think that because it's all to the front of the motor and carbs will drain when you tip the motor and that is exactly where it will run out. Check the airbox seal and make sure the drain hose is connected to it. The compression is pretty good for that motor no problem there no need to look for better #s. If the carbon is in the exhaust it would not leak out where it is should be coming out the prop. I do agree with running a good synthetic oil in your motor and get BRP engine tuner it works better than seafoam.

 

[joshua27]

The air box appears to be sealed and the drain tube is in place. Hopefully it will clear up. I'm going to run some synthetic 2 stroke oil and see if that helps.