4-50
FUEL
E
FUEL PUMP
CHECKING THE FUEL PUMPS
4
1. Check:
• Diaphragm
• Fuel pump valves
Damage
→
Replace.
2. Check:
• Fuel pumps
Reverse air flow
→
Replace.
Checking steps
NOTE:
Do not overpressurize the fuel pump.
Excessive pressure may cause air to leak
out.
(1) Install the Mity vac onto the fuel pump
as shown.
(2) Apply the specified pressure with the
Mity vac.
NOTE:
• Make sure no air comes out of the oppo-
site side of the fuel pump.
• To eliminate any gaps between the fuel
pump valves and the fuel pump body, and
to ensure a better seal, make sure the
inside of the fuel pump is wet (i.e., with
gas).
Mity vac
YB-35956 / 90890-06756
Fuel pump pressure
a
50 kPa (0.5 kg/cm
2
, 7.1 psi)
Fuel pump negative
pressure
b
30 kPa (0.3 kg/cm
2
, 4.3 psi)
4240