Float Test

Make sure the fuel tank is less than half full.
Remove the fuel fill cap to relieve the fuel tank pressure, then reinstall the cap.
Remove the fuel pipe cover. Disconnect the fuel tank vapor recirculation tube (A), and connect a commercially available vacuum pump/gauge, 0-30 in.Hg, to the hose.

Fig 1: Disconnecting Fuel Tank VAPOR Recirculation Tube
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Plug the fuel tank vapor recirculation pipe (B).
Apply vacuum to the fuel tank vapor recirculation tube (A).
- If the vacuum holds, replace the fuel tank vapor control valve (see FUEL TANK VAPOR CONTROL VALVE REPLACEMENT ).
- If the vacuum does not hold, the float is OK. Go to step 1 of the valve test.