fuel tank vent question

[grizzly]

i have this 3gal tank, and when i first got it i would leave the vent closed, and the next morning i would find the sides sucked in about as far as they could go. i was worried about the tank getting deformed over time from this happening so i started leaving the vent cracked open a bit. it has a 1/4" threaded plastic vent, my concern now is do i need to worry about water condensation building up in my tank. i wouldn't think it would,but just wondering what you all do.

 

[CarlF]

leave the vent open a little bit. If you dont, the opposite will happen on a hot day: it will puff up like a balloon!
I accidently left the vent on mine closed last summer. Over the course of the day, the temp climbed to about 95, the tank pressurized and forced about 2 gallons of gas into the carb, through the cylindars & out the exhaust. What a mess!!!

When my boat is parked, I cover the cap with a plastic bowl to keep rain from getting in through the vent. To stop condensation, keep the tank filled up.

 

[ben2go]

If that is the tank you have, cut a 20oz soda bottle down, lay a rag over the cap,and slide the bottle bottom over it.It will keep most of the water out when the boat is sitting and allow the tank to breathe.