Check Valve (Exc. Federal B2000)

Remove check valve from lines. Connect a pressure gauge with tee on the nipple leading to the fuel tank and hold finger over opposite nipple. Fig 1.
Blow though open end of tee fitting. When pressure gauge reads 0.78 - 1.0 psi (0.055 - 0.70 kg/cm² ), the valve should be open.
NOTE: Valve must be held horizontally.

Fig 1: Testing Fuel Evaporation Check Valve
Courtesy of MAZDA MOTORS CORP.