Checking The Fuel Pump; Disassembling The Fuel Pump - Yamaha F25C Service Manual

FUEL

Checking the fuel pump

1. Place a drain pan under the fuel hose
connections, and then disconnect the
fuel hoses from the fuel pump.
2. Connect the special service tool to the
fuel pump inlet.
3. Cover the fuel pump outlet with a finger,
and then apply the specified positive
pressure. Check that there is no air leak-
age.
Vacuum/pressure pump gauge set:
90890-06756
Specified pressure:
50 kPa (0.5 kgf/cm
4. Apply the specified negative pressure
and check that there is no air leakage.
Specified pressure:
30 kPa (0.3 kgf/cm
5. Connect the special service tool to the
fuel pump outlet.
4-5
Fuel system
2
, 7.3 psi)
2
, 4.4 psi)
6. Apply the specified positive pressure and
check that there is no air leakage. Disas-
semble the fuel pump if necessary.
NOTE:
Assemble the fuel pump valves to the fuel
pump body, and moisten the inside of the fuel
pump with gasoline to ensure a good seal.
Specified pressure:
50 kPa (0.5 kgf/cm

Disassembling the fuel pump

1. Disassemble the fuel pump as shown.
2. Push down on the plunger and the dia-
phragm, turn fuel pump body 1 1
approximately 90° to a position where the
pin 2 can be removed easily, and then
remove the pin.
2
, 7.3 psi)
6D55F11