IAW instructions provided in TM 9-2350-267-20.
Drain water and contaminants from the fuel filters by placing a
suitable container under the drain hoses, open the drain cocks,
and turn on the MASTER and FUEL SHUT OFF switches.
appears clean, turn off the MASTER and FUEL SHUT OFF switches and
close the fuel filter drain cocks.
Inspect the APU fuel lines and fittings for possible leakage.
Tighten or replace defective lines or fittings as outlined in TM
If you suspect contaminated fuel, the fuel tanks must be drained
and refilled with new fuel IAW TM 9-2350-267-10.
If air appears to be in the system, disconnect the fuel return
line at the injection pump quick-disconnect.
Use a screwdriver
to push open the disconnect valve.
Place a suitable container
under the quick-disconnect valve and operate the APU fuel pumps
Should the fuel flow appear to be weak or not steady, inspect the
fuel lines for obstructions or restrictions.
Repair or replace
any defective items as necessary. When any repair or replacement
has been accomplished, the fuel system will once again require
Troubleshooting the APU Engine when Engine Lacks Power.
The problems that contribute to the engine lack of power is somewhat similar
to the problems that contribute to engine misfiring.
Apply the following
troubleshooting when the engine does not develop adequate power.
Clean or replace the
Inspect air ducting for obstructions or improper assembly.
Inspect fuel filters as previously outlined
filter elements as necessary.