Injection Nozzle Fuel Flow Check; Fuel Manifold Replacement - Lycoming IO-390-D Series Maintenance Manual

IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual

7. Injection Nozzle Fuel Flow Check

A. Label each fuel injector and fuel line according to cylinder number.
B. Disconnect the fuel line from the injection nozzle (Figure 10).
C. Remove the injection nozzle from the engine cylinder.
D. Connect the fuel lines to the injection nozzles according to the cylinder number.
E. Put the injection nozzles into four clear containers of equal size on a flat surface.
F. Turn the boost pump on and move the throttle and mixture control full forward.
G. Examine the fuel flow from each injection nozzle to make sure the fuel stream is not
scattered (which is an indication of blockage in the injection nozzle) identified as "Incorrect"
in Figure 11.
H. Let approximately 4 to 6 oz. (120 to 180 ml) of fuel to flow into each container. Close the
throttle and mixture control and turn off the boost pump.
I. Measure the level of the fuel. All containers must have the same amount of fuel. A container
with less fuel is an indication of a fuel flow restriction.
NOTICE: If the fuel flow is incorrect, disconnect the injection nozzle and clean the nozzle
according to the "Injection Nozzle Cleaning" procedure in Chapter 05-30. Repeat
the fuel flow check. If cleaning does not correct the scattered stream, replace the
injection nozzle. Fuel injection nozzles are not repairable.
J. Disconnect the fuel lines from the injection nozzles.
K. Install acceptable injection nozzles in the cylinders and connect the fuel lines. Refer to the
latest revision of the Service Table of Limits - SSP-1776 for torque values.

8. Fuel Manifold Replacement

WARNING
DO NOT SMOKE OR HAVE AN OPEN FIRE FLAME OR USE ANY
DEVICE THAT CAN MAKE SPARKS. FLAMES OR SPARKS CAN CAUSE
FUEL IGNITION WHICH CAN CAUSE SERIOUS BURNS, INJURY OR
DEATH.
NOTICE: If this fuel manifold replacement procedure is completed with the engine installed in the
airframe, refer to the airframe manufacturer's instructions for shutting off the fuel and
grounding the aircraft.
© 2020 Avco Corporation. All Rights Reserved
March 2020
Figure 11
Injection Nozzle Stream
73-10
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