Oil leak

[wjhuskey]

Hello. I have a 1998 Mercury 225 EFI on my bassboat. I walked past it the other day in the garage and seen oil on the back of the casing. I know sometimes unburned gas appears on the outer casing after idling but that's not what it is this time. There's more of it this time and the boat hasn't been ran since this appeared. I pulled the hood but couldn't see where it was coming from. I store the motor in the down position. Maybe a deteriorated powerhead gasket? Pic attached

 

[Chris1956]

Smell the oil to make sure it is not gear oil. Gear oil stinks like rotten eggs.

 

[wjhuskey]

Smell the oil to make sure it is not gear oil. Gear oil stinks like rotten eggs.

I did, it didn't seem to have much of a smell.

 

[Chris1956]

OK, not much of a smell means 2 cycle oil. That motor is 2 cycle, right?

 

[Chris1956]

Doubtful the cause is a bad powerhead gasket.

If using oil injection, check the oil lines for leaks. A Merc with oil injection has a reservoir that gravity feeds an oil pump, plus pressure lines to force oil from the boat mounted tank into the engine mounted tank. If the engine mounted tank cap is loose, she will overflow.

 

[wjhuskey]

Doubtful the cause is a bad powerhead gasket.

If using oil injection, check the oil lines for leaks. A Merc with oil injection has a reservoir that gravity feeds an oil pump, plus pressure lines to force oil from the boat mounted tank into the engine mounted tank. If the engine mounted tank cap is loose, she will overflow.

Yes it's a 2 cycle. I've checked the engine mounted tank and didn't see any leakage. Everything under the hood looks clean.