I have a 06 Mercury Optimax 115. I was out Saturday and the boat ran great for the first couple hours. Going to my final spot for the day I came off plane and was idling to the spot. The engine started to sputter/ miss a beat for a second then was fine. I didnt think much of it. After fishing the spot, I cranked up the engine and it started to sputter again (giving it no gas). I gave it some gas and it quit sputtering. Then I stopped the boat and it started sputtering again. Starting trolling looking at my graph and the sputtering stop. Then I tried to get on plane and it sputtered and the engine stop. I could never get it started again. Had to get towed in. When I got it home, I put the engine down and notice an oil/gas mixture coming down from the lower unit. It was coming out pretty good. I have already taken it to C&O to get it looked at because I am no mechanic. I was wondering if any of you have a clue what this maybe. Do I have a big issue here? Thanks in advance.