Purging Air From The Fuel System - Mercury MerCruiser D2.8L D-Tronic Service Manual

FUEL DELIVERY PUMP AND FUEL FILTER

Purging Air From The Fuel System

Absolute cleanliness is required for work on the fuel system, since the injection
pump and fuel injectors have very close tolerances. Even minute particles of dirt
or small amounts of water can impair the function of the fuel injection system.
The practice of draining and replacing the water separating fuel filter, including purging a
new filter of air, is generally the only time for purging air from the system. In most cases the
design of the EDI System will prevent needing to purge the fuel injection pump itself.
However, should it become necessary to purge air from the fuel injection pump proceed as
follows.
NOTE: Place suitable container under the fuel filter and injection pump to catch excess fuel.
1. Bleed air from the water separating fuel filter.
2. Loosen the bleed screw on injection pump.
3. Move plunger on hand pump/primer up and down repeatedly, until an air free stream of
fuel flows from bleed screw.
4. Close the bleed screw on the injection pump. Tighten securely.
5. Connect the battery cables.
6. Start the engine. Check for leaks. If leaks exist stop the engine immediately. Recheck
the filter installation.
Page 5B-16
a - Bleed Screw
b - Expelled Fuel
CAUTION
a
SERVICE MANUAL NUMBER 22
b
71371
90-860074--1 FEBRUARY 2002