"Shortwave Sportfishing" wrote in message
...

I can't believe that 20 gallons of gasoline in a 50 gallon tank will
expand and contract to the point where air movement becomes an issue.
I would think that it's more of a case of barometric pressure, partial
gas pressures of oxygen and humidity that would cause condensation
rather than air movement through the vent.

Yes/No?


The vapors do the expansion/contraction. The liquid gas change is minimal
and basically a non-event.

Think of your red, plastic 5 gallon gas tank. If full and left in the sun
it doesn't change much. Half-full and left in the sun, the sides are
bulging. Take the cap off and hear the expanded vapor/air mixture release.

Eisboch