A vent control system having a closed biased vent valve (10) is used to separate vapor and/or air from a liquid in an enclosed chamber (62). The closed biased vent valve (10) has a float (64) having an upwardly extending float arm (68) which cooperates with a lever arm (14) of the closed biased vent valve (10) to prevent unintended release of vapor or liquid from the enclosed chamber (62). The upwardly extending float arm (68) and the lever arm (14) are coupled to one another when the float (64) is located beneath a designated level in the enclosed chamber (62) and are decoupled from one another when the float (64) rises above the designated level. The vent control system is much less susceptible to vibration induced vent opening than a traditional vent valve. The vent control system is well suited for use in a fuel vapor (30) separator that includes a housing(32) having the enclosed chamber (62) formed within it.