July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!
Rollover Valve
Valve consists of a plunger and a stainless steel ball. When valve is inverted, the stainless steel ball pushes the plunger against its seat, blocking fuel flow through valve.
Fig 1: Charcoal Canister Connections (Typical) Vapors are stored in canister until engine is started.