CHAPTER 6. ENGINE REPAIR INSTRUCTIONS

CHAPTER 6

ENGINE REPAIR INSTRUCTIONS

Section I. ENGINE ACCESSORIES

6-1. General

f. Cleaning, Inspection, and Repair.

This section contains those items which are considered

accessories to the engine. They consist of governor,

(1) Wipe all parts of the generator, except the

generator, starting motor, generator regulator, magneto,

brushes, with a cloth lightly dampened in an approved

radiator, and water pump.

cleaning solvent; dry thoroughly with low pressure

compressed air. Wipe brushes with clean, dry cloth.

6-2. Governor

a. General.

Refer

paragraph

334a

for

(2) Check the size of the brushes; replace

them if they are less than '/8 of an inch long.

description.

(3) Inspect the armature commutator for

b. Removal. Refer to figure 3-12 and remove the

roughness out-of-round or high mica. If any of these

governor.

conditions exist, turn the commutator down on a lathe

c. Disassemble.

Refer

figure

6-1

and

and undercut the mica 13I2: inch. Remove only enough

disassemble the governor.

stock to make the commutator smooth and round. After

undercutting, finish the commutator with No.

d. Repair. Replace any parts that are found

sandpaper. Clean all particles from the commutator and

defective and reassemble the governor.

armature using low pressure, dry, compressed air.

e. Installation. Refer to figure 3-12 and install the

Check the armature for short circuits as described in

governor.

subparagraph (6), below.

6-3. Generator

Caution

a. General.

Refer

paragraph

3-43a

for

Always blow particles off the

description.

commutator in the direction away

from the armature windings.

b. Output Testing.

(4) Check the brush holders for distortion,

(1) Connect the generator and generator

cracks, breaks, or other damage; replace damaged

regulator as shown in figure 6-2. Run the engine to

brush holders.

allow the temperature of the generator to reach 77F.

(5) Replace the brush springs if tension is

(2) The cold output of the generator must be

less than 28 ounces.

18 amperes at 28.5 volts when the generator is turning

(6) Check for short circuits in the armature by

at 1775 RPM.

rotating the armature on a growler with a steep strip

such as a hacksaw blade held firmly on the armature.

c. Removal. Refer to figure 3-19 and remove the

The steel strip will vibrate on the area of the short

generator.

circuit. Short circuits are usually caused by particles

between commutator bars. If short circuits are found,

d. Cleaning and Inspection. Refer to paragraph 3-

clean spaces between the commutator bars .using an

43e and clean and inspect the generator.

undercutting tool and compressed air. If a short circuit

e. Disassemble.

Refer

figure

3-20

and

cannot be corrected, replace the armature.

disassemble the generator.

6-1