Lycoming IO-390-D Series Maintenance Manual page 296

NOTICE: If fitting P/N 74070 is necessary for the fuel line, install this fitting on the fuel
pump prior to installing the fuel pump on the engine.
(4) Install the fuel pump with a new gasket on the accessory housing as shown in Figure 13
with the two washers and two screws.
(5) Torque the screws to 225 to 250 in.-lbs. (25 to 28 Nm).
(6) Connect the fuel lines to the fuel pump. Torque the fuel fitting to 23 to 24 ft.-lb. (31 to 35
Nm). Make sure that the fuel lines are securely connected.
(7) During the "Operational Ground Check" in Chapter 72-00 (which is to be done after all
maintenance is complete), look for fuel leaks at the fuel lines and connections during
engine operation. Identify and correct the cause of any fuel leak. There must not be any
fuel leak when the engine is returned to service.
73-10
Page 270
IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual
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March 2020