Yamaha F400A 2022 - Checking the Fuel Filter Assembly; Checking the Fuel Filter Element; Checking the Fuel Cup Assembly; Checking the Primer Pump

Fuel filter assembly
6-4
Checking the fuel filter assembly
1. Check:
• Fuel inlet holding pressure
Out of specification → Replace the O-ring,
cup assembly, or fuel filter assembly.
a. Connect the special service tool “1” to
the fuel inlet “a”.
b. Block the fuel outlet “b” using a rubber
plug “2”, and then apply the specified
positive pressure for 15 seconds or
more.
2. Check:
• Fuel outlet holding pressure (negative
pressure)
Out of specification → Replace the O-ring,
cup assembly, or fuel filter assembly.
a. Connect the special service tool “1” to
the fuel outlet “a”.
b. Block the fuel inlet “b” using a rubber
plug “2”, and then apply the specified
negative pressure for 15 seconds or
more.
Checking the fuel filter element
1. Check:
• Fuel filter element
Dirt/residue → Replace.
Checking the fuel cup assembly
1. Check:
• Fuel filter cup assembly
Foreign material → Clean.
Cracked → Replace.
2. Check:
• Electrical performance of the water detec-
tion switch.
See “Checking the water detection
switch” (5-28).
Checking the primer pump
1. Check:
• Primer pump holding pressure
Out of specification → Replace the primer
pump.
Fuel inlet holding pressure (posi-
tive pressure)
200.0 kPa (2.00 kgf/cm², 29.0
psi)
Vacuum/pressure pump gauge
set “1”
90890-06945
Pressure/vacuum tester “1”
YB-35956-B
Fuel outlet holding pressure (neg-
ative pressure)
-80.0 kPa (-0.80 kgf/cm², -11.6
psi)
1
ab
OUT IN
2
Vacuum/pressure pump gauge
set “1”
90890-06945
Pressure/vacuum tester “1”
YB-35956-B
Positive pressure
166.7 kPa (1.67 kgf/cm², 24.2
psi)
1
b
a
OUT IN
2