Piper Navajo PA-31 Service Manual page 615

PIPER NAVAJO SERVICE MANUAL'
9-37. ASSEMBLY OF FUEL FILTER.
(Refer to Figure 9-11.)
a. If removed, install by-pass valve spring (8), relief ball (9) and seat (10).
b. Place the filter cartridge (assembled) on the housing stud (5). Ascertain
that the end of the outer tube (3) has positioned itself in the filter body (1).
c. Secure the filter cartridge with nut (4). Torque nut 10 to 15 inch pounds.
Torque check nut (14) against nut (4) 40 to 60 inch pounds.
d. Place bowl gasket (2) on housing and install bowl (15), washer (16) and cap
nut (7). Torque cap nut 60 to 80 inch pounds and safety.
e. Install the filter.
If the filter was not removed, proceed to step c of para-
graph 9-38.
9-38.
INSTALLATION OF FUEL FILTER.
(Refer to Figure 9-9.)
a. Connect the filter and electric fuel pump. Tighten the jam nut on the fitting
between the pump and filter to allow the "O" ring to seat on the non-threaded
portion of the fitting.
b. Position the filter and pump on the mounting brackets and secure.
c. Connect the lines to the filter and pump tee.
d. Connect the electrical leads to the fuel pump.
e.
Turn on the fuel valve and check for fuel leaks.
f. Install the access plate.
9-39.
CLEANING FUEL SYSTEM.
a. To flush fuel tanks and selector valve, disconnect fuel line at the injector.
b. Select a fuel tank, turn on the electric fuel pump and flush fuel through the
system until it is determined that there is no dirt and foreign matter in the fuel
valve, lines or tank.
During this operation, agitation of the fuel within the tank
will help pick up and remove any dirt.
Repeat this procedure for each tank.
c. When all tanks are flushed, clean the filter assembly.
Reissued: 10/12/79
FUEL SYSTEM
3B23