I have a 2003 Mercury 125 HP. I am docking this year at a boat club and have been storing with the motor tilted all the way to have lower unit out of the water. The other day I was walking down the dock and noticed a oil slick behind my boat. To make a long story short I figured out that the oil is leaking out from the oil tank cap. I checked it out closely and the O ring seems to be fine. The cap is marked to turn to right to close and to left to open. I am not sure why as I can pull the cap off when it is turned all the way to the right. I can see in the throat of the tank what looks to be sort of a thread, but I see nothing on the cap that would go into that thread.
Could I possibly have the wrong cap on this motor? The cap is yellow, with an O ring about half way up on its base and again I see nothing on the cap that would benefit me by locking it in place by turning it.