The exploded diagram at BRP does not show any kind of seal or o-ring on the vent screw.
LINK to BRP:
http://12.2.215.22/pub/default.asp?SessionId=969b0db0f5e14fb4926ba00393257c6a&Lang=EN&brands=EJ,ATV,SEADOO,SKIDOO,SPORTBOAT,LYNX,ROADSTER
The seal for the drain plug is too big to fit in the...