SERVICE MANUAL McCULLOCH

McCULLOCH
Drive
Model Bore Stroke Displ. Type
Titan 50 45 mm 32 mm 51 cc Direct
(1.77 in,) (1,26 in.) (3.1 cu. in.)
Titan 57 47 mm 33 mm 57 cc Direct
(1,85 in.) (1.30 in.) (3.5 cu. in.)

MAINTENANCE The Titan 57 saw is equipped with a Regular grade unleaded or leaded gaso-
carburetor heater valve designed to line is recommended, but use only one
SPARK PLUG. Recommended spark heat the intake air to prevent icing of type. Changing fuel types can cause en-
plug is Champion DJ8J or equivalent. carburetor when operating in cold, gine damage. Use a separate container
Spark plug electrode gap is 0.025 inch damp conditions. Ib operate heater, re- when mixing oil and fuel.
(0.63 mm). Note that spark plug has a move engine cover (2—Fig. MC13-3) and All models are equipped with an au-
tapered seat and does not require a gas- close the flapper valve located in engine tomatic chain oil pump and a manual oil
ket. Tighten spark plug to a torque of cover. This will allow carburetor to draw pump. Oil output of automatic oil pump
108-135 in.-lbs, (12.2-15,2 N-m), a mixture of outside air through lower is adjustable. Pump adjusting screw is
duct in cover and warm air from the located between clutch assembly and
CARBURETOR. All models are powerhead. Flap must be in "open" po- crankcase (Fig. MC13-2) and is accessi-
equipped with a Walbro HDA diaphragm sition when operating in warm weath- ble through opening in bottom of saw.
carburetor Refer to CARBURETOR er to avoid engine overheating. Adljustment screw is turned fully clock-
SERVICE section for overhaul and ex- wise at the factory. Taming adjustment
ploded view of carburetor. IGNITION. All models are equipped screw counterclockwise will decrease
Initial adjustment for both low speed with a capacitor discharge electronic ig- oil flow and turning screw clockwise
and high speed mixture needles is one nition system. Ignition components are will increase oil output.
turn open from a lightly seated position. contained in an ignition module located McCulloch Chain, Bar and Sprocket
Make final ac^ustment with engine adjacent to flywheel. Ignition timing is Oil is recommended for use in all tem-
warm and running. Be sure air filter is not adjustable. Ignition module must be peratures. The use of automotive type
clean before making final carburetor ad- positioned so there is 0.010-0.012 inch oil is also acceptable. Select oil viscosi-
justment. (0.25-0,30 mm) gap between module ty according to ambient temperature.
Adjust idle speed screw (1—Fig. MC13- laminated legs and flywheel magnets. Use SAE 10 oil when temperature is be-
1) so engine idles just below clutch en- Loosen module mounting screws and low 40°F (5°C) and SAE 30 oil when
gagement speed. Adjust idle mixture move module as necessary to obtain temperature is above 40°F (5°C).
needle (2) so engine will accelerate specified gap.
cleanly without hesitation. Adjust high REPAIRS
speed mixture needle (3) to obtain op- LUBRICATION. The engine is lubri-
timum performance under cutting load. cated by mixing oil with fuel. Recom- CRANKCASE PRESSURE TEST. An
Saw should not be operated with high mended fuel:oil ratio is 40:1 if using improperly sealed crankcase can cause
speed mixture needle set too lean McCulloch oil, or 20:1 when using any the engine to be hard to start, run
(turned too far clockwise), as engine other brand of oil designed for two- rough, have low power and overheat.
could be damaged from lack of lubrica- stroke air-cooled engines. If McCulloch Refer to ENGINE SERVICE section of
tion and overheating. Engine speed at oil is not used, the addition of a fuel this manual for crankcase pressure test
wide-open throttle with no-load should stabilizer (such as STA-BIL Gas Stabiliz- procedure. If crankcase leakage is indi-
be 11,000-11,500 rpm. Reatyust idle er or equivalent) is recommended to cated, pressurize crankcase and use a
speed screw, if necessary, so chain does minimize the formation of fuel gum soap and water solution to check
not move when engine is idling. deposits. The use of oil designed for au- gaskets^ seals, pulse line and castings for
tomotive use is not recommended. leakage.

Fig. mci3'2—Automatic oii

pump adjusting screw is lo-
cated in bottom of saw. Him
screw clockwise to increase
oil flow.
-OILER
ADJUSTMENT
Fig. §4013-1—Drawing sftowing iocation of Idle SCREW
speed adjusting screw (1), low speed mixtum nee-
die (2) and high speed mixture needle (3}.

niustratioiu couftesy McCuUoch Oxp.

377
McCULLOCH CHAIN SAW

TIGHTENING TORQUES. Refer to The cylinder bore is chrome plated ton pin and new piston rings should also
the following table for tightening torque and should be inspected for flaking, be installed. Inspect needle bearing (6)
values: scoring or excessive wear. Cylinder in small end of connecting rod and re-
should be renewed if chrome plating is new if pitted, worn or damaged.
Crankcase halves 70 in.-lbs.
(7.9 N-m) worn through.
Inspect piston for scoring or excessive Piston must be installed so arrow on
Cylinder .90 in.-lbs. wear. Piston skirt diameter wear limit piston crown points toward exhaust
(10.1 N-m) is 1.761 inch (44.75 mm) for Titan 50 and port. Heating piston with a heat lamp
Oil pump 30 in.-lbs. 1.841 inch (46.79 mm) for Titan 57. Pis- will ease installation of piston pin. In-
(3.4 N-m) ton pin boss inside diameter wear limit stall new piston pin retainers (3). Lubri-
Ignition module 35-45 in.-lbs. is 0.3955 inch (10.05 mm) for all models. cate piston rings and cylinder bore with
(4.0-5.0 N-m) Maximum allowable ring groove width light coat of SAE 30 oil before install-
Air filter box 20 in.-lbs. is 0.315 inch (0.80 mm) for all models. ing cylinder. Apply Loctite Gasket Elim-
(2.2 N-m) Piston may be reused if piston skirt is inator to cylinder mounting surface. If
discolored, but is not scored or exces- intake boot (9-Fig. MC13-3) was re-
Carburetor 45 in.-lbs. moved from cylinder shroud (12), rein-
sively worn. Piston rings should be re-
(5.0 N-m) newed. If piston is renewed, a new pis- stall boot using Loctite BlackMax adhe-
Clutch 150-168 in.-lbs.
(17.0-19.0 N-m)
Flywheel 150-168 in.-lbs.
(17.0-19.0 N-m)
Starter pawl plate 75 in.-lbs.
(8.5 N-m)
Chain brake band 85-90 in.-lbs.
(9.6-10,1 N-m)
Spark plug 108-135 in.-lbs.
(12.2-15.2 N-m)
MAIN FRAME. The main frame
(34—Fig. MC13-3) can be pivoted away
from power head for access to all hoses
and carburetor, or saw can be separat-
ed into two sections—main frame as-
sembly and power head assembly.
Ib pivot main frame away from pow-
er head, remove air box cover (2) and
air filter (3). Pry ignition switch/choke
control assembly (19-Fig. MC13-4) out
of control handle. Remove two air box
retaining screws and pivot power head
away from main frame. Tb separate
main frame from power head, discon-
nect fuel line, oil lines and carburetor
linkage. Remove two forward anti-
vibration mounts (12) and separate main
frame from power head.
PISTON, RINGS AND CYLINDER. Tb
disassemble, remove engine cover and
pivot main frame away from power
head as outlined above. Remove start-
er housing (14—Fig. MC13-3) and air baf-
fle (15). Unbolt and remove muffler as-
sembly (18) from cylinder. Remove spark
plug. Disconnect throttle rod, choke rod
and fuel line. Remove carburetor
mounting screws and anti-vibration
mount screws, then remove carburetor
(5) and air box (6). Pry rear mount as-
semblies (19, 20 and 21) off cylinder roll
pin. Remove cylinder shroud (12). Re-
move cylinder mounting screws and tap
cylinder with plastic mallet to break 31
cylinder-to-crankcase gasket compound.
Withdraw cylinder from piston. Remove Fig. fi/ICi3-3—Expioded view of chain saw components typicai of all models.
1. Front handle 10. Spacer 19. Mount retainer
piston rings (2—Fig. MC13-5) from pis- 2. Engine cover 11. Clamp 20. Rear mount Needle bearinfl
ton ring grooves. Remove piston pin re- 12. Cylinder shroud 21. Mount earner 28. ^^P^ocket
3. Airfilter 29. C u ch drum
4. Shield 13. FMel line 22. Bar adjustment
tainers (3) and use special tool No. 5. Carburetor 14. Starter housing screw 30. Uutch shoes
236020 or similar piston pin removal 15. Air baffle 23. Bar plate 31. I^b
6. Air box
7. Sleeve 16. "O" ring 24. Bar
tool to press piston pin (5) out of piston 17 Sleeve 25. Chain brake assy. -iJ- rlate
and connecting rod. 9. intake boot Is: Muffler 26. Washer 34. Main frame assy.

Illustrations courtesy McCulloch Corp.

378
 SERVICE MANUAL McCULLOCH
sive or equivalent fuel resistant
adhesive.
CRANKSHAFT, CONNECTING ROD
Fig. MC13-4—Exploded view AND CRANKCASE. The crankcase
of main frame components.
1. Oil tank cap
halves (13 and 17-Fig. MC13-5) must be
2. Fuel pick-up assy. separated to remove crankshaft assem-
3. Fuel tank cap bly (9). For access to crankcase, power
4. Trigger release pin
5. Trigger pin head must be separated from main
6. Main frame frame as previously outlined. Remove
7. Trigger release
8. Trigger assy. spark plug and insert a loop of rope in
9. Spring spark plug hole to lock piston. Remove
10. Oil strainer
11. Oil suction tube chain brake, guide bar and chain, clutch
12. Front mount
13. Oil tank vent (left-hand threads) and oil pump. Re-
14. Manual oil pump move starter housing, air baffle and fly-
15. Oil inlet tube
16. Oil outlet tube wheel. Unbolt and remove cylinder
17. Choke rod from crankcase. Remove crankcase
18. Throttle rod
19. Ignition/choke mounting screws. Heat one of the crank-
control assy. case halves in area of main bearing, then
20. Fuel line
21. Fuel tank vent carefully tap end of crankshaft to sep-
arate crankcase halves. Heat the other
crankcase half and tap crankshaft from
case half. Use suitable puller to remove
worm gear (10) and bearings (8) from
crankshaft. Remove oil seals (12 and 22)
from crankcase and oil pump housing.
The crankshaft and connecting rod
are a unit assembly. Check rotation of
connecting rod around crankpin and re-
new crankshaft assembly if roughness,
P, Roll pin excessive play or other damage is not-
1. Cylinder
2. Piston rings ed. Renew ball bearings (8) if roughness
3.
4.
Piston pin retainers
Piston
or other damage is indicated. Press
5. Piston pin bearings and worm gear onto crankshaft
6. Needle bearing until they are seated against shoulders
7. Roll pin
8. Ball bearings of crankshaft. New seals (12 and 22) can
9. Crankshaft & be installed after crankshaft is installed
connecting rod assy.
10. Worm gear in crankcase. Lubricate crankshaft with
11. Ignition module oil prior to installing seals.
12. Seal
13. Crankcase half Heat crankcase halves in area of main
14. Gasket
15. Dowel pin bearings prior to installing crankshaft
16.
17.
Bar bolts
Crankcase half
assembly. Assemble crankcase using
18. Mounting screws new gasket (14). Tighten crankcase
19. "O" ring mounting screws before crankcase
20. Oil pump
21. Connector halves cool to 70 in.-lbs. (7.9 N*m), then
22. Seal retorque screws after case cools. Rotate
23. Seal retainer
24. Oil inlet hose crankshaft to make certain it turns free-
25. Sleeve ly. If not, disassemble and locate
26. Flywheel
problem.

CLUTCH. Refer to Fig. MC13-3 for an

exploded view of clutch assembly. Ib re-
move clutch, first remove chain brake
(25), guide bar (24) and chain. Remove
engine cover (2) and remove spark plug.
Insert a knotted rope in spark plug hole
to lock piston. Unscrew clutch hub (31)
clockwise (left-hand threads). Remove
and separate clutch components.
Clutch shoes (30), hub (31), spring (32)
and plate (33) are serviced as an assem-
bly. Inspect clutch drum (29), needle
bearing (27) and sprocket (28) for exces-
sive wear and renew as necessary.
Lubricate clutch drum needle bearing
(27) with grease. Install clutch assembly
24 and tighten to 150-168 in.-lbs. (17.0-19 0
MC13-S—Exploded view of engine typical of all models. N-m).

Dlustrations courtesy McCuUoch Corp.

379
McCULLOCH CHAIN SAW
OIL PUMP. All models are equipped Note the plate position in relation to er end. Wrap rope on pulley in a clock-
with a manual oil pump (14—Fig. MC13- starter pawls (7) so plate can be rein- wise direction viewed from flywheel
4) located in main frame and an auto- stalled in same position. Lift out rope side of pulley. Tighten rope pulley re-
matic chain oil pump (20—Fig. MC13-5) pulley (4). Rewind spring is contained taining screw to 50 in.-lbs. (5.6 N*m). Tb
located on clutch side of crankcase. The within housing (3). If spring is to be re- put tension on rewind spring, pull a loop
automatic oil pump is operated by a moved, use caution to prevent spring of rope back through starter housing
worm gear (10) on the crankshaft. from uncoiling uncontrolled. Rewind opening and turn pulley and rope two
For access to automatic oil pump, re- spring and housing are available only as turns clockwise. Release rope and check
move chain brake assembly, bar and an assembly. starter operation. Rope handle should
chain and clutch assembly. Remove oil Inspect all parts for wear or damage retract snugly against starter housing.
pump mounting screws, disconnect oil and renew as necessary. Rope length Be sure spring does not bottom out
hose (24) and remove oil pump assem- should be 46-48 inches (117-122 cm). when rope is fully extended. It must be
bly from crankcase. Tb remove manual If rewind spring should become disen- possible to rotate pulley at least V^ turn
gaged from housing, it may be rewound clockwise before rewind spring bottoms.
oil pump, pivot main frame away from
power head. Disconnect oil lines (15 and by hand in clockwise direction from out-
16—Fig, MC13-4), remove pump retain-
ing nut and remove pump from main
frame.
Thoroughly clean all components and
inspect for wear or damage. Both the
automatic oil pump and manual oil
pump are serviced as unit assemblies.
An adjusting screw is located in bot-
tom of automatic oil pump. Turn screw
clockwise to increase oil output or coun-
terclockwise to decrease oil flow. Fig. i\/IC13-6—Exploded view
of citain braiie assembiy.
1. Brake housing
CHAIN BRAKE. All models are 2. Brake lever
equipped with a chain brake system de- 3. Washer
4. Latch slider
signed to stop chain movement should 5. Brake latch
kickback occur. The chain brake is ac- 6. Pivot pin
7. Pivot pin
tivated when operator's hand strikes 8. Bar plate
chain brake lever (2-Fig. MC13-6), 9. "E" ring
10. Screw
which trips latch (5) and releases spring 11. Brake band
(12) to pull brake band (11) tight around 12. Brake spring
13. Pin
clutch drum. Pull back chain brake le- 14. Chain stop 11
ver to reset mechanism.
Tb check for proper chain brake op- 12
eration, place saw on flat surface and 13
run at full throttle. Push chain brake le-
ver forward to activate brake. The chain
should stop moving immediately. No ad-
justment of chain brake is required. If
brake fails to operate properly, disas-
semble and inspect for problem.
Tb disassemble chain brake, move
brake lever (2-Fig. MC13-6) forward to
engage brake and relieve brake spring
tension. Tb remove brake band (11), ro-
tate guide plate (8) and remove ''E'' ring
(9) and retaining screw (10). Disconnect
brake spring (12). Drive out pins (6 and
7) to remove brake lever (2) and latch
(5).
Inspect all components for evidence
of wear or damage and renew as neces-
sary. Brake band (11) should be renewed
if worn to a thickness of 0.021 inch (0.5
mm) or less. Tb reassemble, reverse dis-
assembly procedure.
REWIND STARTER. Rewind starter
components are contained in starter
housing (2—Fig. MC13-7). Tb disassem-
ble, remove starter housing, detach rope
handle (1) and allow rope to wind slow-
Fig. ii/IC13-7^Expioded view of rewind starter assembiy.
ly onto pulley (4). Unscrew retaining 1. Rope handle 4. Rope pulley 7 Pawls 10. Pawl plate
screw (12) and remove pawl plate (10), 2. Starter housing 5. Rope 8. Bushing U. Washer
12. Screw
spring (9), bushing (8) and pawls (7). 3. Spring/housing assy. 6. Springs »• »pnng

Illustrations courtesy McCulloch Corp.

380