Operating instructions
Table Of Contents
- 1 Introduction
- 2 General Description
- 3 Special Tools and Equipment
- 4 Disassembly
- 5 Cleaning, Repair and Replacement
- 6 Inspection
- Definitions
- Magnetic Particle Inspection
- Critical New Part Dimensions
- Fluorescent Particle Inspection
- Dimensional Inspection
- Protective Coatings
- Crankcase Inspection
- Crankshaft Inspection
- Camshaft Inspection
- Connecting Rod Inspection
- Gear Inspection
- Piston Inspection
- Cylinder Inspection
- Inspection Chart
- Crankcase Stud Heights
- Mag Particle Inspection Procedures
- Table of Limits
- Torque Specifications
- General Torques
- Table of Limits Chart
- 7 Assembly of Subassemblies
- 8 Final Assembly and Test
- 9 IO-520-M
- 10 IO-520-BB, CB and MB

MARCH 1982 8-9
FIGURE 8-13. BOTTOM VIEW WITH VALVE MECHANISM
AND OIL SUCTION TUBE INSTALLED PERMOLD
CRANKCASE.
1. Oil suction tube
2. Screws
3. Pushrod housing.
8-11. FUEL PUMP -TYPICAL OF SANDCAST
CRANKCASE (See Figure 4-1).
a. Lubricate fuel pump drive gear and coupling with
Gredag No. 44.
b. Install a new gasket on two lower left rear
crankcase studs. Install coupling in gear and install
fuel pump and vapor separator. Secure with two sets
of attaching parts.
8-12. FUEL PUMP -TYPICAL OF PERMOLD
CRANKCASE (See Figure 4-2).
a. Lubricate fuel pump drive coupling with Gredag
No. 44.
b. Install coupling in pump. Install new gasket and
mount fuel pump and vapor separator on crankcase
studs. Secure with two sets of attaching parts.
8-13. STARTER DRIVE ADAPTER (See Figure
4-16).
a. Apply a thin coat of Loctite Gasket Eliminator
#515 to the crankcase surface only.
CAUTION ...Sealant must be applied sparingly to
prevent contamination of the engine oil system.
b. Lubricate spur gear and mesh it with crankshaft
gear as adapter is placed in position. Seat adapter
against gasket. Secure adapter to sandcast crankcase
with two sets of nuts and washers and two bolts and
lockwashers. Attach lower generator support bracket
as shown in Figure 8-10. Secure adapter to permold
crankcase with five sets of nuts, plain washers and
lockwashers.
8-14. GENERATOR (See Figure 4-13).
a. Install upper support bracket components (7
through 12) and secure it with bolt (6).
b. Position crankcase mounting bracket bushings (20)
on each side mounting hole and press sleeve (21)
through bushings. Position generator (18) so that it
straddles mount bracket with the rear flange between
washer and support bracket. Align holes in flanges
and secure bracket assembly (17), lower support
bracket (22) and generator (18) to bracket (23) with
washers (19) and bolts (16).
8-15. ALTERNATOR ASSEMBLY (See Figure
4-15).
a. Install the baffle support assembly (4). Secure with
crankcase through bolt attaching parts.
b. Install Woodruff key (7), gear hub (12), spring
(11), driven gear assembly (9, 10), washer (8) and nut
(6). Tighten nut to 450 inch pounds torque. If slots of
nut do not align with cotter pin hole in alternator shaft,
nut may be tightened further, not to exceed 500 inch
pounds torque. Install cotter pin (5).
c. Install new gasket (13) on flange of alternator.
d. Install the alternator (3) on the crankcase mounting
flange. Install four sets of attaching parts (1, 2).
Torque bolts to value specified in Table of Limits,
Section VI. Secure bolt heads in pairs with lockwire.
8-16. MAGNETO AND ACCESSORY DRIVE
ADAPTERS (See Figure 4-5).
a. Place two new gaskets on two upper four stud
mount pads at the rear of the crankcase so that oil
holes in gaskets are aligned with crankcase oil outlet
holes.
b. Install two adapter assemblies with oil holes
aligned with crankcase oil outlet holes. Attach both
with plain washers, lockwashers and nuts.