I found a crack in the vent plug washer on my slingshot wizard board. Luckily I cought it in time and no water entered my board. I suspect the sharp ringed edge on the board where the washer sits might have caused this; so I lightly sanded it smooth and got rid of any burs on the plastic plug. Just putting this out there to double check your vent plug washer for signs of failure. This washer was less then 5 months old. Don't always trust all edges are smooth for your washers to sit on.

Thanks, checked my o ring and it too was damaged, replaced and going to sand recess too.
It's kinda awkward to sand around the recessed hole. I just taped some sandpaper to the end of a small paintbrush.
For the vent plug I wrapped some sandpaper around a flat bade and did the burs around the plastic vent plug. For some reason my vent plug is 3d printed or molded plastic witch leaves a line of burs down the middle. Hope this helps.
Yeah, I was thinking about the recess, that way sounds good- thanks. My screw is SS with no burrs. Could not find the exact o-ring locally, found one slightly thicker, workes good but wants to stay in the recess, using a Q-tip plastic shaft to get it out..
Checked out the recess with a magnifier/light, big burr at the bottom side wall, sanding revealed more burrs (revealed white under coat). All smooth now. I have been lubing the o-ring with silicone grease to make sure it seals and maybe protect it too.
Yep, mine wore out really fast this year. Picked up some spare ones at the hardware store. These plastic vent screws are screwy. You can't tighten them like the metal vent screws. The plastic can't be tightened as nearly as tight because you will strip the head of the screw and crush the washer. So I just snug the plastic screw up against the washer not too tight, then back the screw off a hair, then back snug again, then back off a hair again and re-snug. I do this about 3-4 times to make sure the plug is well seated against the washer, creating a slight bond, but not crushing the washer. If I snug it up too tight, the head of the screw will mushroom the washer, and will take on a slight amount of water. If the screw isn't tight enough, then you will take water in as well. It seems to be a skill in itself just to snug up a stupid vent screw. But it's now mastered!!![]()
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It is most likely from over-tightening.
The standard o-ring is generally an 8x1.5mm
I change mine from this size to 2 or 2.5mm cross section and that changes the process from sealing solely between the plug and the base of the recess to also sealing on the inner edge of the recess thus achieving 2 point sealing.
The added benefit is that it is extremely hard to over-compress the o-ring as it can not be extruded from under the plug because of the contact with the inner edge of the hole.
It is most likely from over-tightening.
The standard o-ring is generally an 8x1.5mm
I change mine from this size to 2 or 2.5mm cross section and that changes the process from sealing solely between the plug and the base of the recess to also sealing on the inner edge of the recess thus achieving 2 point sealing.
The added benefit is that it is extremely hard to over-compress the o-ring as it can not be extruded from under the plug because of the contact with the inner edge of the hole.
Yup, that is what I did, but now the o-ring stays in the recess and not on the screw.