Austin Big Seven starting problem

[John Mason]

For what it is worth I find with my Ruby it maybe something to do with how well the tank is vented. When I put petrol in ( I never put in more than 3 gallons) the car runs fine. I leave it in the garage and soon the whole garage has that lovely smell of petrol. Over the next few weeks this petrol aroma diminishes and with it the starting efficiency of the car. It would appear to me that with age the petrol has evaporated off the spirit element that vapourizes easily without warming. The car normally will run on old stale petrol okay once I have got it going on new fuel. I put this down to the engine and manifold being warm and thus enabling the petrol to vapourize more easily.
Could it be that some cars have more than necessarily over vented petrol tanks.
Has anyone else got views on this.

John Mason