Operating instructions

MAY 1980 8-11
b. Place a hose clamp on each end of cylinder intake
tube so it faces center tube. Push end tubes into hose
previously installed on center intake tubes. Work
hose clamps over ends of hoses, but not past bead. Do
not tighten at this time.
c. Push a hose on each front and rear intake tube and
install a clamp on overlapping portion behind tube
bead. Tighten these clamps.
d. Lay a new gasket on intake flange of each cylinder.
Position each assembly of tubes and hoses on proper
bank of cylinders and adjust each tube so it seats
squarely on cylinder port.
e. Attach each intake flange to its cylinder with four
sets of attaching parts (16,17,18). Position clamp on
two center hoses on each side inside tube beads and
tighten.
f. For IO-520-B engines push rear hose on No.1 and
No.2 intake tubes back onto tube until clear of ends.
Position hose (4) on rear manifold assembly. Slide
clamp assembly (2) over hose. Install air throttle body
assembly and control assembly on bottom of sump
and secure with bolt and washer (17, 18, Figure 4-2).
Slide other end of hose (4) onto air throttle body, and
other end of No.1 and No.2 intake tube hoses onto rear
manifold assembly. Position clamps and tighten.
g. For IO-520-A, C, F, J, K and L push hose clamp on
both elbows (5, 6) and push elbows into connecting
hoses of rear intake tubes. Position clamps and
tighten only enough to hold tubes.
h. Install clamp (11) and bracket (10) on balance tube
(13). Push tube ends into connecting hoses installed
on front intake tubes. Position clamp and secure to
sump with attaching parts (8, 9). Position clamp
assemblies (12) over tube beads and tighten.
i. While engine is inverted, secure brackets (38) to
sump with corner sump bolts and washers (23, 24).
Place bracket (63) between free ends of brackets (38)
and align holes. Attach all three with screw (27),
washer (26) and nut (25). Turn engine upright.
j. Secure IO-52O-A, F, J, K and L support bracket
(37) to upper magneto drive adapter studs and idler
gear support studs with attaching parts (33, 34, 35).
Assemble IO-520-C support brackets (48 through 55).
Secure bracket (51) to lower magneto drive adapter
studs and bracket (48) to right and tachometer drive
housing.
k. Position air throttle assembly on bracket (36) and
secure with attaching parts (28,29, 30). Place hose
clamp over each hose (3) on elbows (5, 6) and work
hoses onto throttle body position and tighten clamp.
Secure IO-520-A, F, J, K and L support bracket to air
throttle body with attaching parts (31, 32). Secure IO-
520-C support bracket (48) and (51) as illustrated.
8-23. INDUCTION SYSTEM, IO-520-D (See
Figure 4-7).
a. Push a new hose (2) on either end of center intake
tubes. Slide one hose clamp (11) to a position
midway on overlapping portion. Turn each clamp so
that a screwdriver can be aligned with its screw and
yet clear of the stand when tube is installed. Tighten
screw only enough to hold clamp in position.
b. Place a hose clamp (11) on each end of cylinder
intake tubes so it faces center tube. Push end tubes
into hoses previously installed on center intake tubes.
Work hose clamps over ends of hoses, but not past
bead. Do not tighten at this time.
c. Push a hose on each front and rear intake tube and
install a clamp (1) on overlapping portion behind tube
bead. Tighten these clamps.
d. Lay a new gasket (17) on intake flange of each
cylinder. Position each assembly of tubes and hoses
on proper bank of cylinders and adjust each tube so it
seats squarely on cylinder port.
e. Attach each intake flange to its cylinder with four
sets of attaching parts (12, 13, 14). Position clamp on
two center hoses on each side inside tube beads and
tighten.
f. Push hose clamp on elbows (3, 4) and push elbows
into connecting hoses of rear intake tubes. Position
clamps and tighten only enough to hold tubes.
g. Install clamp (8) and bracket (7) on balance tube
(10). Push tube ends into connecting hoses installed
on front intake tubes. Position clamp, and secure to
sump with attaching parts (5, 6). Position clamp
assemblies (9) over tube beads and tighten.
h. While engine is inverted, position air throttle body
(19) with hoses (2) and brackets (1) in relative
position.