Checking The Fuel Pump; Disassembling The Fuel Pump - Yamaha 55DEHD Service Manual

FUEL

Checking the fuel pump

1. Place a rag under the fuel hose connec-
tions, and then disconnect the fuel hoses
from the fuel pump.
2. Connect the special service tool 1 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 1:
90890-06756
Specified positive pressure:
50 kPa (0.5 kgf/cm
4. Apply the specified negative pressure
and check that there is no air leakage.
Specified negative pressure:
30 kPa (0.3 kgf/cm
5. Connect the special service tool 1 to the
fuel pump outlet.
4- 4-7
Fuel system
1
69R40120
2 , 7.3 psi)
1
69R40130
2 , 4.4 psi)
6. Apply the specified positive pressure and
check that there is no air leakage.
Disassemble the fuel pump if air leaked.
Specified positive pressure:
50 kPa (0.5 kgf/cm

Disassembling the fuel pump

1. Remove the 3 screws securing the pump
together.
NOTE:
To disassemble the fuel pump, refer to page
4-5.
2. Check the diaphragms. Replace the
diaphragms if deteriorated or tears.
3. Check the check valves. Replace the
check valve if bend or damaged. Also,
check the fuel pump body. Replace the
fuel pump body if damaged.
1
69R40140
2 , 7.3 psi)
68840010
6885J11