New Plastic Gas Tank - Fixing Expansion

[Bassn7]

I've read that the new plastic tanks have a closed system with poor vapor release. Would it be OK to just put some small holes in the screw on cover to release that pressure? Thoughts please....

 

[GA_Boater]

No, you will make a leaker when the tank expands or if you carry a fullish tank by the handle.

I've had no trouble with an EPA tank other than looking like a peeled watermelon.

 

[tpenfield]

Are we talking portable fuel tanks?

Vapor pressure - all those tanks end up being fairly round after a few years regardless of their original shape

Best not to mess with it from a safety perspective

 

[roscoe]

you could always leave the cap slightly loose when not in use or transporting it.

 

[David Young]

I have 2 metal 6 gallon gas tanks. One started leaking where the gas line hooks up. Instead of fixing the one leaking I bought a plastic 6 gallon gas tank from Walmart. It blew up like a balloon and had to unscrew the lid to release pressure so I could slide it from where the gas tanks sit while boating . I bought a repair kit for the metal tank that was leaking . I use the plastic gas tank at home to run sea foam through my motor

 

[ahicks]

you could always leave the cap slightly loose when not in use or transporting it.

^X2^

 

[robert graham]

Good old government/EPA/ventless gas tanks.....that pressure build up can also cause the fuel system fittings leading to and on the motor to leak.....ever so slightly crack open that gas cap(maybe 1/8 turn) enough for tank to breath and don't fill tank all the way to the top.....this for above board/portable tanks---not under deck/ built- tanks where no gas fumes are acceptable....

 

[07whitendirty]

I bought 1 for my previous boat (poontoon) and it expanded and looked like a balloon. I drained it, washed it and returned it. Got on craigslist and got a couple if used vented tanks and out new fittings in them.

 

[ahicks]

West Marine offers some replacement caps that might work out for you. Others may as well, but I was checking this one out in a store not too long ago.

https://www.westmarine.com/buy/moeller--low-profile-manually-vented-fuel-cap--13099544