If you cut the fuel neck from an old mower or tiller (briggs or tecumseh), you can find new vented ( 2 way) caps for cheap.
Here is a check-ball vent I made today for $0, but the check-ball shuts off fuel flow if there's no return hose from carb. Best to use a motorcycle dirt-bike tank vent ($10) for gravity feed.
My home-made vent (without check ball it works, but can leak fumes when parked)
Motorcycle vent $10 for good metal one
Originally Posted by tooljunkie
i have considered an automotive fuel cap and filler neck from one of the old cars in my back 40.
cut filler neck off and welt to whatever tank i build.
another one is crank out something on my lathe,with an inlet valve to let air in so fuel will drain out petcock.and a check ball to keep gas in when its sloshing.
i have a couple old coleman cookstoves,the filler is a nice size.
oh.forgot why i was here,like the bike,the ammo box idea is cool.
aftermarket snowmobile parts suppliers have rear fuel storage tanks,roughly one gallon.
cap and gas line fitting ready to go.