Mercury 25 EFI Service Manual page 198

Service Procedures
3. Separate the fuel pump diaphragm housing from the check valve assembly.
NOTE: The check valve assembly is not serviceable. Replace as needed.
a
4. Squeeze the fuel pump plunger and the diaphragm together. Rotate the fuel pump diaphragm housing to access the
diaphragm pin. Remove the diaphragm pin.
5. Inspect the fuel pump diaphragm and the fuel pump diaphragm spring for damage. Replace as needed.
Fuel Lift Pump Reassembly
1. Assemble the fuel pump components.
a c
b
2. Install the diaphragm spring onto the diaphragm.
3. Insert the diaphragm with the spring into the fuel pump diaphragm housing. Ensure the diaphragm shaft is in proper
alignment to accept the diaphragm pin.
4. Install the plunger spring and plunger onto the fuel pump diaphragm housing.
5. Compress the diaphragm and plunger.
6. Insert the diaphragm pin into the plunger.
Page 3C-14
a
b
c
d
10034
e
d
a
b
c
d
10034
© 2016 Mercury Marine
10033
a - Fuel pump plunger
b - Diaphragm pin
c - Fuel pump diaphragm housing
d - Diaphragm
f
a - Plunger
b - Diaphragm pin
c - Plunger spring
d - Fuel pump diaphragm housing
e - Diaphragm spring
f - Diaphragm
10037
a - Fuel pump plunger
b - Diaphragm pin
c - Fuel pump diaphragm housing
d - Diaphragm
a - Check valve assembly
(not serviceable)
b - Fuel pump diaphragm
b
housing
90-8M0105568 eng MARCH 2016