Suction Valve

Blow air through suction valve air inlet section. Air should flow smoothly through to valve outlet. See Fig 1 . If air does not flow smoothly, reed valve is stuck closed. Replace reed valve.
Blow air through valve outlet. If air flows out inlet, reed valve is broken or stuck open. Replace reed valve.
To check suction valve after it has been disassembled, inspect gasket, inlet case and outlet case for damage (cracks). Clean reed valve with gasoline and inspect for waves, cracks or dents in reed valve seat.
Inspect for a broken or cracked point of reed valve, or a rusty stopper. Replace parts as necessary. See Fig 2 .

Fig 1: Suction Valve

Courtesy of SUBARU OF AMERICA, INC.

Fig 2: Exploded View of Suction Valve

Courtesy of SUBARU OF AMERICA, INC.