6-8.1 GENERAL.
a. Work on a clean bench and protect gear teeth and oil seal surfaces from nicks and scratches. b. Repair by standard shop practices, using standard shop tools unless otherwise stated.
c. Repair or replace pans as indicated by inspection.
d. If the condition of any part is questionable following inspection and repair, replace the part.
e. If replacement parts are available, replace all gasket seals, and O-rings each time they are removed. If origi- nal Parts are reused, check closely for leaks.
f. Lubricate lips of new oil seals with an approved, clean, light grease before installation. Use a soft brush to apply.
g. Refer to chapter 7for listings of replacement parts.
h. Disassemble components only to the extent necessary to effect desired repairs.
i. Read procedures in full before starting repairs. Pay particular attention to safety precautions.
j. Tables appearing throughout this chapter provide data that may be useful for intermediate and depot level maintenance.
6-8.2 PRELIMINARY PROCEDURES AND SAFETY INFORMATION. Prior to performing any work on the diesel engine, proceed as follows:
WARNING
Rotating machinery can cause injury or death. Ensure the engine is shut down before working on equipment and that the starter is tagged OUT-OF- SERVICE.
a. Shut down the engine and tag OUT-OF-SERVICE. b. De-energize the electrical starting system components.
NOTE
Unless an engine overhaul or removal is being performed, it is not necessary to proceed further.
c. Drain the cooling system. d. Drain the lubricating oil. e. Disconnect the fuel lines.
f. Remove the air cleaner and mounting bracket g. Disconnect the exhaust piping.
h. Disconnect the throttle controls.
i. Disconnect, tag, and remove any electrical equipment and wiring.
j. Disconnect any other lubricating oil lines, fuel lines, or electrical connections. k. Close the sea water supply valve and drain the sea water system.
l. Remove the heat exchanger and other related cooling system parts. m. Separate the engine from the marine transmission.
n. Remove the engine mounting bolts.
WARNING
To prevent injury or death, ensure extreme care and proper lifting devices are used during handling. The equipment is heavy.
CAUTION
To prevent damage to equipment, the diesel engine lifting device should be adjusted so the lifting hooks are vertical.
S9233-C9-MMA-010
o. Using a spreader bar with a suitable sling and adequate chain, lift the engine from its base. Mount the engine on an overhaul stand suitable to support the full weight of the engine.
WARNING
To prevent injury or death, ensure the engine is securely mounted to the overhaul stand before releasing the lifting sling; engine damage may result if the engine breaks away from the overhaul stand.
p. Ensure the engine is securely mounted to the overhaul stand, then release the lifting sling.
q. Prior to disassembly, clean the exterior of the engine using a steam cleaner or a high-pressure water wash. 6-9. STARTER MOTOR.
6-9.1 REMOVAL. Remove the starter motor according to the following steps. Unless otherwise noted, callouts refer to figure 7-2.
a. Identify and disconnect the positive lead cable from the battery. b. Identify and tag all wires attached to the starter motor terminals.
c. Remove twelve point screws (26) securing the starter motor to the flywheel housing. d. Withdraw the starter motor from the flywheel mount and move to a suitable workbench.
6-9.2 DISASSEMBLY. Disassemble the starter motor according to the following steps. Unless otherwise noted, callouts refer tofigure 7-2.
a. Using a scribe or similar sharp-pointed tool, remove two core plugs (25) from drive end shield (7), exposing two field terminal screws.
b. Remove the two field terminal screws.
c. Loosen Phillips head screw (54) and remove commutator cover (55), and lining (56).
NOTE
Removal of the brush lead screws also frees the field coil connections.
d. Remove brush lead screws and lock washers (71 and 23); raise brush springs and trigger (38) and remove brushes (72).
NOTE
Use caution not to lose the steel ball which is under pressure from the spring.
e. Using a wrench, carefully unscrew and remove end cap (57). f. Remove steel ball (59) and spring (60).
WARNING
To prevent serious eye injury while removing/installing retaining ring(s), wear safety eye protection. Ensure retaining ring(s) is secure in the ring groove.
g. Remove internal retaining ring (66), retaining pad (58), and shim washers (67). h. Unscrew and remove two thru-bolts (69) and two lock washers (70).
NOTE
When removing the commutator end shield, retain the shims for reassembly; end float adjustment is simplified by fitting the original shims.
i. Carefully remove commutator end shield (73) and shim washer (67) from the end of the armature shaft. j. Using a mallet, tap drive end shield (7) away from the housing; remove the end shield complete with arma-
ture (85). Remove and discard sealing ring (84).
CAUTION
To prevent damage to equipment, a soft-jawed vise, cloth, or cardboard should be used to protect parts.
k. Secure the armature in an armature clamp or a soft-jawed vise. Unscrew pinion stop nut (88) in the direction of starter rotation and remove thrust washer (87) and spring (86).
l. Remove core plug (1) and spring (2) from the drive end shield.
m. Release the ball lock mechanism by pushing the drive end shield (7) toward the armature (85). With the col- lar (48) held in position, unscrew the pinion until the helix disengages. Slide the pinion assembly (83), together with the drive end shield, off the armature shaft. Collect, note location, and retain lock ring balls and overspeed balls (82). Remove the armature from the clamp or vise.
WARNING
To prevent serious eye injury while removing/installing refining ring(s), wear safety eye protection. Ensure retaining ring(s) is secure in the ring groove.
n. Remove and discard external retaining ring (52) from the end of the pinion sleeve. o. Remove trip plate (5 1), washer (50), lock collar spring (49), and collar (48).
NOTE
Inspect the pinion for burrs or similar damage before withdrawing it from the drive end shield.
p. Remove any burrs from the pinion and withdraw pinion assembly (83) from the drive end shield. S9233-C9-MMA-010
q. Detach the flexible lead from moving contact (37); remove the link to the binding post on the moving con- tact.
r. Using a suitable punch, remove securing rivets (47) to free resistor (45) from the drive end shield; remove resistor bushing (44) and spacers (43).
s. Remove main terminal nuts (16), lock washers (15), screw (18) and lock washer (17). Remove washers (13 and 14), sealing ring (12) and insulator bushing (11). Rotate main terminal (8), 180 degrees axially and remove from the drive end shield (7) along with support (9) and insulator (10).
t. Remove nuts (24), lock washers (23), washer (22), and insulating bushings (20 and 21) from solenoid termi- nals (19). Push the solenoid terminal into the drive end shield and clear of its hole.
u. Remove self-tapping screws (30), lock washers (23), and solenoid assembly (27) along with the main termi- nal insulator. Remove similar components from the adjacent relay (R) terminal.
6-9.3 CLEANING AND INSPECTION. Clean and inspect the starter motor according to the following steps.
a. Inspect the brushes for wear. If excessively worn when compared with a new brush, they should be replaced. Ensure the brush holders are clean and the brushes do not bind in the holders. The full brush surface must ride on the commutator to provide Proper performance. Check by hand to ensure the brush springs provide firm contact between the brushes and commutator. If the springs are distorted or discolored, they should be replaced.
NOTE
Do not turn the commutator or undercut the insulation on the motor. Use 240- grit emery paper to clean the commutator. If the commutator cannot be cleaned, replace the armature assembly.
b. Check the armature for shorts, open circuits, and grounds according to the following steps.
1. Short circuits are located by rotating the armature in a growler with a steel strip (such as a hacksaw blade) held on the armature. The steel strip will vibrate on the area of the short circuit. Shorts between bars are sometimes produced by brush dust or copper between the bars.
2. Open circuits may be located by inspecting for loose connections at the points where the conductors am joined to the commutator. Loose or poor connections cause arcing and burning of the commutator. If the bars are not badly burned, leads originally soldered to the riser bars can be re-soldered. Check for insula- tion to ground by means of a 500-volt megger type tester between any commutator segment and the arma- ture shaft. Resistance should be a minimum of one megohm.
3. Grounds in the armature can be detected by the use of a test lamp. If the lamp lights when one test probe is placed on the commutator and the other test probe on the armature core or shaft, the armature is grounded and must be replaced.
c. Field coils. Using a test lamp, check the field coils for grounds and open circuits according to the follow- ing steps.
1. Grounds. Disconnect the field coil ground connections. Connect one test probe to the field frame and the other to the connector. If the lamp lights, the field coils are grounded and must be repaired or replaced. 2. Open circuits. Connect test lamp probes to the ends of the field coils. If the lamp does not light. the field coils are open. If the field coils need to be removed for repair or replacement, a pole shoe spreader and pole shoe screwdriver should be used. Care should be exercised in replacing the field coils to prevent
grounding or shorting as they are tightened in place. Where the pole shoe has a long lip on one side, it should be reassembled in the direction of armature rotation.
d. Solenoid coils and contacts. The coils can be checked for shorts or open circuits by measuring current con- sumption at nominal voltage. A link should be made between the green lead and the terminal lug, refer to table 6-2 andfigure 6-4.
Table 6-2. Solenoid Test Data
Starter Type Ammeter in Supply Circuit Read Ammeter
CA4524 Insulated Return
Apply 24 volts to black and green leads*
Check current consumption is approxi- mately 16 amperes.
*
On some starter solenoids, the green lead is replaced by a yellow lead.
CAUTION
To prevent overheating, do not leave the pull-in winding energized more than 15 seconds. The current draw will decrease as the winding temperature increases. The purpose of the R terminal is to short out the ignition resistor during cranking, thereby providing high ignition coil output.
1. With all leads disconnected from the solenoid, make test connections to the solenoid switch terminal and to ground or to the second switch terminal (if present) to check the hold-in winding. Compare the amme-
Figure 6-4. Starter Motor Solenoid S9233-C9-MMA-010
ter reading with the specifications. A high reading indicates a shorted or grounded hold-in winding and a low reading indicates excessive resistance. To check the pull-in winding, connect from the solenoid switch terminal to the solenoid motor terminal.
2. Examine the contacts and, if necessary, clean them with white spirit or very fine carborundum paper. The first stage gap should be 0.083 inch (2.1 mm) with a bottom limit of 0.076 inch (1.93 mm) and a maxi- mum of 0.098 inch (2.5 mm). Press down the plunger and ensure the second stage contacts make, but only after the trigger is tripped. If the contacts are badly burned, the gap excessive, or the coils appear to have overheated, the solenoid should be replaced as a complete unit.
e. Dismantling the solenoid. To replace defective components, dismantle the solenoid according to the follow- ing steps. Unless otherwise noted, callouts refer tofigure 7-2.
1. Remove rivets (29) securing trigger guide (39) and the rivets securing contact stop (28); remove the con- tact stop and trigger guide. Examine the trigger guide for wear on the pivot points; replace the trigger guide, as required.
2. Remove plunger (36), spring (33), moving contact (37), and spring (35) as a complete assembly.
3. Unsolder the solenoid leads connected to the fixed contact lug and remove the fixed contact assembly (figure 6-4).
f. Reassembling the solenoid. Following component replacement, reassemble the solenoid according to the following steps.
1. Locate the fixed contact assembly on the solenoid; ensure the contact plate rivet holes align with those in the solenoid coil plate.
2. Replace plunger (36), moving contact (37), and springs (33 and 35). The rectangular-shaped extension on one side of the moving contact must face the two rivet holes for the trigger guide (39).
3. Push the solenoid plunger fully home. With the plunger held in this position, replace contact stop (28) and trigger guide and rivet both into position.
4. Solder the solenoid leads, as required, to obtain circuit continuity.
5. Verify correct first stage contact gap of 0.076 inch to 0.096 inch; a slight gap adjustment can be obtained by bending the brass contact stop.
g. Commutator end bearing. Ensure commutator end bearing bushing (68) is tight in its housing. Check the side play between the armature shaft and bearing. If the side play is excessive, replace the end bearing bush- ing as follows.
1. Press the old bearing bushing out of the commutator end shield.
NOTE
There should be no machining attempted on the commutator end shield.
2. Inspect the commutator end shield bore for any damage, clean thoroughly, and apply a coat of light oil; press the replacement bearing bushing in the commutator end shield.
h. Drive end shield. Inspect and repair the drive end shield according to the following steps.
CAUTION
The retaining pad must be removed to prevent oil starvation of the bearing after assembly. On new drive end shields, the retaining pad is fitted in the oil way.
1. Check the internal diameter of the drive end shield (7). If bearing bushing (6) is worn, the drive end shield must be replaced with a new unit.
2. Ensure lubrication pad (4) is free to move under the influence of spring (2).
i. Pinion. If the pinion teeth are badly worn or damaged, replace the pinion with a new unit. Ensure the new pinion has the same number of teeth and is a free-sliding fit on the armature shaft. If necessary, lightly lap the pinion bore and shaft with a fine lapping paste. Remove all traces of lapping paste using a bottle brush to ensure absolute cleanliness of the pinion helix. If the pinion is fitted with an oil seal in the bore, all burrs or sharp, edges must be removed or the seal will tear. Install a new oil seal with the U-channel facing toward the pinion teeth end (figure 6-5).
j. Springs. Ensure the starter motor springs are not damaged, discolored, or deformed and retain their ten- sion. Refer totable 6-3.
Table 6-3. Spring Tension
Spring Compressed Length Tension
Lock Spring 0.375 in. (9.53 mm) 1.69 to 1.94 lbs Recoil Spring 1.313 in. (33.35 mm) 26.50 to 29.50 lbs Pinion Spring 1.250 in. (31.75 mm) 7.75 to 8.50 lbs Pinion Spring (oil
sealed starter)
1.469 in. (37.3 mm) 9.81 to 10.19 lbs
k. Commutator.
1. If the commutator surface is dirty or discolored, it may be cleaned with a very fine grade of glass paper. Do not use emery cloth or carborundum paper.
2. In cases where the surface is badly pitted or grooved, set the armature up in a lathe and skim the commu- tator. With a rough cut, remove just enough copper to clear traces of the damage. After this, a very light cut should be taken using a diamond or tungsten carbide tip to obtain a high quality surface finish.
WARNING
Never turn a stream of compressed air on anyone. Severe injury or death could result.
3. Remove all traces of dust using dry, compressed air. The minimum diameter to which the commutator can
Figure 6-5. Installing Oil Seal S9233-C9-MMA-010
be machined is 1.56 inch (392 mm). Radius at the juncture of the risers and commutator must not exceed 0.040 inch (1.0 mm). The risers should not be skimmed and the commutator must not be undercut, as car- bon tracking from the brush may occur.
l. Armature shaft. Inspect the armature shaft for any burrs caused by the steel lock balls and overspeed balls. Carefully remove any visible burrs. Inspect the shaft helices for damage or excessive wear. Clean the helices with an approved solvent and apply a small quantity of lubricating grease.
m. Field windings. Remove and replace field windings (80) according to the following steps. Unless otherwise noted, callouts refer to figure 7-2.
1. Using a pole shoe screwdriver, unscrew pole shoe screws (78). Remove the pole shoes and windings; note their original positions within the starter housing (figure 6-6). Mark number 1 position with tape or scribe mark on housing.
NOTE
As an aid to correct assembly, the pole shoes are numbered and must be replaced in the same positions as original. Otherwise, they might foul the armature during operation.
2. Fit the replacement windings into the housing and replace the pole shoes in their original positions (figure 6-6).
3. Carefully align the pole shoes in the housing; insert and torque the pole shoe screws (78) 25 to 30 lb-ft using a pole shoe screwdriver. When completed, ensure no space exists between the mating surfaces of the pole shoes and the housing.
n. Brush gear. Using a 10-volt megger-type tester, check the insulation between all brush holders and the starter motor frame. The insulation resistance must be not less than one megohm. Ensure all brush holders am secure.
o. Brushes. During overhaul, always renew the brushes to ensure maximum life between overhaul periods. Brushes must be fitted in complete sets and replacement brushes must be well bedded. To accomplish this, proceed as follows:
Figure 6-6. Positions of Pole Shoes and Windings
CAUTION
To prevent damage to equipment, a soft-jawed vise, cloth, or cardboard should be used to protect parts.
1. Place the armature in an armature clamping device or a vise with protected jaws. Wrap a strip of fine glass paper (not emery cloth or carborundum) around the commutator with the abrasive side outward; secure the glass paper in place with an approved adhesive.
2. Slide the commutator end shield (73) onto the armature shaft; fit the brushes and place the brush springs in position.
3. Rotate the end shield in the opposite direction to the normal direction of rotation of the armature until the brushes are bedded over 80 percent of the contact surface.
4. Retain the brushes in the respective holders and remove the drive end shield from the armature. 5. Thoroughly clean all dust and abrasive from all components.
6. Remove the glass paper from the commutator and remove all traces of adhesive.
p. Brush springs. The brush spring pressure should be within the range of 6 to 7.5 lbs. Using a suitable spring balance hooked under the lip of the spring, remove the brushes from the holder, raise the lip to the height of the brush. If the spring pressure is incorrect replace the springs.
6-9.4 REASSEMBLY. Reassemble the starter motor according to the following steps. Unless otherwise noted, callouts refer tofigure 7-2. Refer to table 6-1 for special tools required for reassembly.
a. Remove any burrs or sharp edges on segments (34); place spring (35) on a clean, flat surface and position the four segments inside the spring so they lie end-to-end in a circle; install the spring in the outer groove of the segments.
b. Place the solenoid switch on the workbench, coil end facing upward. Gently push the spring and segment assembly into the solenoid plunger bore so it fits into the recess provided.
c. Install split protection collar (tool 6244-6) in drive end shield (7) to protect oil seal (3) and insert pinion assembly (83). Remove the split protection collar.
d. Place terminal insulator (10) under main terminal (8) of the assembled solenoid switch (figure 6-4); the end with the hole must be upright.
e. Insert the solenoid assembly in the drive end shield and secure with self-tapping screws (30) and lock wash- ers (23).
f. Reinstall anodized metal strip support (9) on the inside face of terminal insulator (10).
g. Place insulator bushing (20) over solenoid terminal (19), add the solenoid terminal tag black lead (figure 6-4) over the terminal, and push it through the hole in the drive end shield. Install insulating bushing (2 1), lock washer (23), and nut (24).
h. Repeat step f and step g to connect the green (or yellow, as applicable) return lead to the R terminal. i. Press down the plunger (36) and insert main terminal (8) in position from inside the housing, through the
anodized metal strip and insulator, and into the hole in the drive end shield. Install insulating bushing (11) sealing ring (12), washers (13), plain washers (14), lock washers (15), and nut (16) finger tight.
j. Insert lock washer (17) and Phillips head screw (18). Torque nut (16) to 5 lb-ft. S9233-C9-MMA-010
k. Reinstall collar (48) to the pinion assembly (83) pinion sleeve; ensure the 45-degree chamfer inside the col- lar is facing the solenoid assembly.
WARNING
To prevent serious eye injury while removing/installing retaining ring(s),