Re: 1998 115 spl black oil from lower unit?
Your exhaust exits thru the center of the prop.<br />The black part is carbon deposits from the exhaust, the oil part is unburnt tc-w3 oil.<br /><br />This is pretty much normal for 2 stroke motors.<br /><br />You may be running a little rich or have a fouled sparkplug, but there is likely nothing that is wrong at all.<br /><br />If however, you have a browninish ooze that smells of gear lube, then you have a leak in one of the lower unit seals.<br /><br />With the warmer weather you will see more of it.<br /><br />As for the engine speeding up but losing power, I believe the prop hub is worn out (spun hub).<br /><br />A spun prop is...<br />Ok, a prop is made of two parts. The round cylinder with the blades attached, and the part inside the cylinder. The two parts are held together by a piece or rubber which is pressed between the two parts.<br /><br />When the prop strikes a hard object like a rock, the rubber "hub" is supposed to slip, to prevent severe damage to the lower unit and engine. When the rubber gets older, it can slip from just the force applied by the engine. Usually a spun prop will work at slow engine speeds, but begins to slip as the engine speeds up. Then it will slip completely and the engine will rev faster.<br /><br />You can check the prop by scribing or painting a line on the prop, from the center, across the rubber, onto the outside. Take the boat for a test run, make sure to accellerate hard, a few times. Then look at the line you created. If it is still a straight/continuous line, the prop is ok. If the line is broken, the prop hub is spun.<br /><br />It can be fixed (rehubbed) at a prop shop.
