Mooney M20TN, Service And Maintenance Manual

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MOONEY AVIATION COMPANY, INC.
M20TN SERVICE & MAINTENANCE MANUAL
Page
Date
6
2006
Rev Date
28--00--01 -- FUEL FILLER CAP ASSEMBLY MAIN-
TENANCE
Fuel filler port cap assemblies should be inspected pe-
riodically for proper sealing, condition of O--rings and
should be serviced occasionally to prevent hard to
open or close conditions.
Aero 300 Fuel Fill Caps: 2.25” (Optional on 31--0080
thru 31--TBA.
610213--001 (Bat Inc)
610213--003 (Newton)
610213--005 Locking Type (Bat Inc)
610213--007 Locking Type (Newton)
Replace O--Rings at 5 years or unusual wear part num-
ber #225 FPM 75.
1. The O--ring seal (1) (Figure 28--2) around the cap
assembly should be kept clean and free of dirt or grit
that might cause abrasive action on seal or mating
flange. Occasional lubrication with petroleum jelly or
Tri--Flow (Teflon Lubricant) will keep O--ring soft and
pliable.
2. The shaft (2) running through center of cap hous-
ing, that actuates the rotating lock plate (3) should be
lubricated occasionally with Tri--Flow, or equivalent, to
prevent binding while opening or closing cap assembly.
This should also lubricate the O--ring (4) that seals this
shaft.
-- WARNING --
Water can enter the fuel tank through a loose fit-
ting or damaged cap. This should be corrected
as soon as possible.
3. The sealing capability of each cap assembly
should be checked periodically and at each annual in-
spection. This can be accomplished per the following
procedures:
A. Remove cap assembly from wing filler port and
inspect O--ring (1) for damage, cracks or brittleness.
Remove and replace if needed.
B. Adjust tension of shaft (2) and rotating lock plate
(3) by removing cotter pin (5) from nut (6) so cap as-
sembly handle (7) can be opened, turned and shut with
hand pressure and still provide necessary seal of cap
assembly to keep water from entering fuel tank.
NOTE:
Fuel selector should be in the OFF position be-
fore proceeding with paragraph C to pressurize
the fuel tanks.
-- CAUTION --
Use only one--half pound (0.5 psi) of air pressure
in tank.
C. Connect rubber hose to each tank’s vent line.
Apply ONLY one--half pound (1/2 psi) air pressure.
Check for fuel cap leaks by soaping circumference and
shaft area of filler cap assembly and observing
bubbles. Replace O--ring if bubbles are observed and
adjustment of lower nut (6) does not stop leak.
5
R28--2
6
2
1
4
3
7
FUEL FILLER CAP ASSEMBLY MAINTENANCE
FIGURE 28--2
28--00--01
AUGUST 2010