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oil leaking from cap

BiXLL

New member
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.
 
Could be. Best thing to do is just fill your tank 2/3 full. At full tilt it will just reach the top of the neck. But the oring may look good but not be and the lid may have been jammed buy the PO. I had the same problem and a new lid/gasket kit solved the problem but I still only fill 2/3 full and carry a can of oil just in case.

Mark
 
Could be. Best thing to do is just fill your tank 2/3 full. At full tilt it will just reach the top of the neck. But the oring may look good but not be and the lid may have been jammed buy the PO. I had the same problem and a new lid/gasket kit solved the problem but I still only fill 2/3 full and carry a can of oil just in case.

Mark
I ordered a new cap and O ring, hopefully that will solve my problem?
 
Mine leaked a year ago. The "O" ring looked good. I replaced the ring and it stopped leaking. Got it at a high volume autoparts center; not a chain store. Cost me $.50.
 
Update: After getting the new cap assembly I now know what was wrong. My old cap was not squeezing itself together forcing the O ring out to make a seal when I turned it. The new one works perfectly and I can now tilt all the way up even with the oil reservoir filled.
 
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