Auxiliary Fuel System; Removal Of Auxiliary Fuel Tank - Cessna SKYMASTER 336 1964 Service Manual

a. Remove the four spent conduit tubes (17), one
at each selector valve (5) and one at each selector
gear box (16), and remove control rods (37).
b. Remove access covers from bottom of wings
below selector valves and remove selector gear
box handles and cover. Leave handles off.
c. Remove upper cover on selector valves and
turn gear (29) so that arrow on top face of gear
points to OFF position with gear catch in detent.
Arrow will be pointing to one o'clock position on
left selector valve and to seven o'clock position on
right selector valve.
A mirror will be needed to
see the arrow with selector valves installed in the
aircraft. When selector valves are out of aircraft,
set them in these positions before installing them.
NOTE
Rigging holes are provided in selector valve
cover and gear. These holes align when the
valve is in the off position. Using these holes,
the valve may be checked to be in the off posi-
tion without removing the cover, by inserting
a 3/16 inch pin through holes after removing
screw which plugs hole in cover. If the se-
lector valve is not in this position the system
cannot be correctly rigged.
d. Install long stop screw (44) in the hole to the left
of centerline in the forward selector gear box cover
(42). Install long stop screw (44) to the right of
centerline in rear selector gear box cover (42).
e.
Rotate shaft of forward selector gear box clock-
wise (counterclockwise for rear selector gear box)
until gear (40) strikes stop screw. Remove stop
screws.
f. Insert control rod (37) into selector gear box
and run control rod (37) through until it hits gear
in selector valve. The square on the selector gear
box shaft and the sides of the selector gear box
should be parallel within ± 3°.
g. If sides of shaft and sides of selector gear box
are not parallel, pull control rod (37) back from
selector valve and rotate control rod three to six
turns as required to parallel the sides of shaft and
sides of selector gear box, while control rod is
against selector valve gear. One turn of control rod
moves shaft approximately 5. 5°.
h. With control rod against selector valve gear
and shaft paralleled, rotate forward selector gear
box shaft 180° clockwise (180° counterclockwise
for rear selector gear box shaft).
NOTE
If sides of shaft and sides of selector gear
box are not parallel within ± 3° when selector
valve is in detent, repeat steps "g" and "h."
i.
Install long stop screw in hole to right of center-
line and short screw in hole to left of centerline in
the forward selector gear box. Install long stop
screw in hole to left of centerline and short screw
in hole to right of centerline in the rear selector
gear box.
j.
Install the four spent conduit tubes (17).
k. Install selector gear box cover and selector
gear box handles.
NOTE
Install handles so that handle pointer is in
the auxiliary position.
1. Rotate selector gear box handle to OFF position,
inspect that selector valve is in OFF position as
outlined in note after step "c."
11-39. REMOVAL AND INSTALLATION OF FUEL
LINES.
Fuel lines may be removed and installed
using figure 11-3 as a guide.
NOTE
Observe the general precautions listed in
paragraph 11-2.
11-40. AUXILIARY FUEL SYSTEM.
11-41.
The optional auxiliary fuel system is com-
posed of an additional tank installed in each wing be-
tween the cabin and boom. Each tank has a capacity
of 19 gallons, of which 18 gallons are usable, giving
an additional total fuel capacity of 38 gallons. Fuel
from the auxiliary tanks flows directly into the
standard fuel selector valves; therefore, standard
plumbing of the main fuel system is not affected.
11-42.
REMOVAL OF AUXILIARY FUEL TANK.
Removal of either auxiliary fuel tank is accomplished
through the top of the wing. To remove either auxil-
iary tank proceed as follows:
a.
Place fuel selector valve in the OFF position.
b.
Completely drain tank to be removed through
quick-drain valve in bottom of tank. Quick-drain
valve can be removed to expedite fuel draining.
NOTE
Support outer wing panel and tail boom with
cradle supports, before removing fuel tank
cover, to prevent wing and boom deflection.
c.
Remove auxiliary fuel tank cover from top of
wing by removing screws around outer edge of cover
and around fuel filler opening.
d.
After screws are removed, the forward edge of
the cover must be pulled aft from under the wing
leading edge skin.
Retain gaskets between filler
neck and top wing cover.
e.
Remove bolts from retaining straps securing
tank to wing structure.
f. Disconnect wires from fuel quantity transmitter.
g. Disconnect fuel outlet line at tank.
h. Disconnect fuel vent line at tank and remove line
by pulling up and forward to remove line from grom-
mets in wing structure.
i. Disconnect scupper drain line by loosening
clamp on hose just outboard of tank and pull hose
free.
j.
Carefully lift tank from wing cavity.
11-15