Outer Limits 4x4 Board

Pump has died and i have it out, leaving the fuel tank entrance hole open.

Anyone see a problem with this if I crack the windows and leave it under the carport (battery is disconnected)

I'm assuming from the little info above, its accessed from in the car?

cover the hole with a plastic bag with a rag in it, then lay something on top to weigh it down, it will keep most of the vapour in.

Yeah the entrance hole into the tank is under the back seat.
I'll bag it, rag it and weight it, thanks