I'm going to try to provide as much information as I know regarding my issue and ask some questions on how I can try to pinpoint where the issue is coming from. My GT 150 has always run well, no major repairs under my ownership (6 years) and fires up on the first turn and purrs like a kitten. I mostly fish small lakes on the weekends so the motor is used sparingly. This weekend I took it out on a large lake where we did quite a bit of running around, and trolled at idle speed for a couple hours as well. After pulling it out of the water I noticed a little black oil running down the lower unit and showing on the motor saver. By the time I got home with the boat, there was more oil on the motor saver. I pulled the cover and it appears that there is an oil line running down from where the plugs are - it's not thick just noticable. When I was at Grand lake last year for my vacation i noticed the same thing, not quite as bad but it did drip down some black colored oil. I changed the plugs after that thinking the seals where bad. I am guessing oil could also come out of the exhaust but I can see a darker line where it looks like oil trails down from the front of the motor, down the lower unit, and onto my motor saver. It appears that there is oil residue in the bottom of the cowl, in the front of the engine (below the air intake and carbs, near where the block connects to the lower unit) and the gasket between the lower unit and block is stained with oil in the front portion as well. I'm guessing I don't have a leak issue or the motor wouldn't run as well as it does. This is probably a dumb question but do I need to use a torque wrench for spark plugs? and if so then I probably need to start there and get new plugs again and torque them down correctly and run the motor a bit and see if I get the same problem. Are there other areas I need to check? Thanks in advance for any help or suggestions on trying to pinpoint the problem and / or fix the issue.