lower unit fill/drain plug question?
when i drained the lower unit oil i noticed that the vent screw had a gasket on it. then when i took the fill/drain screw i noticed that it did not. Now i know that my friends out board screw doesn't have a gasket, mine is a stern drive. Is this a problem?
Could i use O rings from an auto parts or no?
- Harry ButtcrackLv 79 years agoFavorite Answer
ALL outboard drain and vent screws have gaskets (seals). These seals are about a buck each, and can be purchased at any marine supply store, Cabelas, Bass Pro, etc. These seals are made of a compression type material and are 1 use only, should be changed every time you remove the drain and vent screws. They not only seal the oil in and the water out, but act as a "lock washer", preventing the screw from loosening due to vibration. Have a good look in the screw hole, your missing seal may still be there. O rings do not work.
- ericLv 59 years ago
I've had several boats over the years. One out of 4 of the outboards didn't have a gasket. I've owned two saildrives which are basically inboard motors with a lower unit, and one of those (the newest one actually) didn't have a gasket. So the absence of a gasket isn't unheard of. If there isn't a gasket, you MUST use the thread sealant (with PTFE) that comes in a tube. To be safe, buy it from a marina store or boat supply place to be sure it is marine grade.
I would never use something purchased from an auto parts store, again, just to be on the safe side.
- mrfixit643Lv 59 years ago
They should all have a gasket on them because without one you will get water in your lower unit.Most lower units use a gasket but there are a couple that do use on o ring.The gaskets are not expensive maybe a buck or two at most so you should use the proper ones to ensure you have no water get into your drive.