4 stroke smoking..

[Boat of Us 2]

Hi

I own a Mercury 90hp 4 stroke 2004.
It has less than 100 hrs.

I recently changed the spark plugs and noticed one had abit of oil on it. I also noticed that it smokes alot from the exhaust which is definatly not normal for a 4 stroke.

Also, when motor is running, I hear a squiky noise. I checked the strap and it is nice and tight so the sound is from below that.

Does anyone know what's going on. I'm abit discourage...

Thanks