McCulloch 32CC TRIMMER User manual

Service Manual
IMPORTANT: READ SAFETY RULES AND INSTRUCTIONS CAREFULLY
PRINTED IN USA FORM NO. 769-00942
This Service Manual is not a substitute for the Operator’s Manual. You must read, understand
and follow all of the directions in this manual as well as the Operator’s Manual before working
on this power equipment.
(10/2003)
32cc String Trimmer
Power Head
MCCULLOCH CORPORATION P.O. BOX 31567, TUCSON, AZ 85751-1567
NOTE: These materials are for use by trained technicians who are experienced in the service and repair of outdoor power
equipment of the kind described in this publication, and are not intended for use by untrained or inexperienced individuals.
These materials are intended to provide supplemental information to assist the trained technician. Untrained or inexperienced
individuals should seek the assistance of an experienced and trained professional. Read, understand, and follow all instructions
and common sense when working on power equipment. This includes the contents of the product’s Operators Manual, supplied
with the equipment. No liability can be accepted for any inaccuracies or omission in this publication, although care has been
taken to make it as complete and accurate as possible at the time of publication. However, due to the variety of outdoor power
equipment and continuing product changes that occur over time, updates will be made to these instructions from time to time.
Therefore, it may be necessary to obtain the latest materials before servicing or repairing a product. The company reserves the
right to make changes at any time to this publication without prior notice and without incurring an obligation to make such
changes to previously published versions. Instructions, photographs and illustrations used in this publication are for reference
use only and may not depict actual model and component parts. © Copyright 2005 MTD Products Inc. All Rights Reserved
MTD Products LLC - Product Training and Education Department

1
1. INTRODUCTION
North American distribution rights to the McCulloch
product line are new to MTD for the 2004 season. The
trimmers are similar in some ways to the MTD South-
West (RYOBI) products that we have offered for the
past three years.
The architecture of both units is based on a cantilever
crankshaft. The McCulloch is piston ported, while the
MTDSW engine has a reed valve. Some of the service
techniques are similar, but not identical.
2. TRIMMER HEADS
2.1. One trimmer head available on the McCulloch
products is nearly identical to the MTDSW Tap-
N-Go. The operating principle is the same, but
the parts are different enough that they are not
fully interchangeable. See Figure 2.1.
2.2. There is also a McCulloch version of the large
tap-n-go head. It is used on the straight shaft
trimmers, and rotates in the opposite direction of
the small one.
Figure 2.1
McCulloch version
of small tap-n-go
2.3. Another trimmer head that is used on McCulloch
string trimmers resembles a cross between the
MTDSW Speed Spool and the MTDSW Tap-N-
Go head. See Figure 2.3.
2.4. A refill consists of 15’ - 20’ of .080” trimmer line.
2.5. To install line, cut it to length. Two equal-length
half-portions may be used, or one full length line
may be installed, then trimmed after installation.
See Figure 2.5.
Figure 2.3
McCulloch trimmer head with
simplified loading
Figure 2.5
Single-length method
McCulloch 32cc Trimmer

McCulloch 32cc Trimmer
2
2.6. Align the arrows on the spool with the arrows on
the housing. See Figure 2.6.
2.7. Insert a length of trimmer line through each eye-
let. There are two sheaves for line in the spool,
separated by a narrow groove. The line must
enter the narrow groove. See Figure 2.7.
2.8. From the eyelet, the line will be channeled up
under the bump knob by a set of ramps in the
spool. See Figure 2.8.
2.9. The ends of the line are looped-through the
anchors to hold them in place, then pulled-tight.
NOTE: With the arrows aligned, the line can also
be installed from the inside-out, by removing the
bump knob.
2.10. The final step is to rotate the spool in the direc-
tion indicated by the arrows, drawing the line into
the head. See Figure 2.10.
2.11. Stop winding when each end of the line is about
6” long.
2.12. Press the bump knob and pull on the line to
manually test the trimmer head. Do not push the
housing off it’s seat while testing.
Figure 2.6
Housing
Spool
Arrows
(marked for
clarity)
Figure 2.7
Eyelet
Center
groove
Figure 2.8
Ramps
Bump knob
removed for
clarity
Bump knob
Anchors
Figure 2.10
Inset: arrow on spool, marked
for clarity

McCulloch 32cc Trimmer
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2.13. If repair is required, remove the bump knob, and
withdraw the spool. See Figure 2.13.
2.14. Check for: tangled line, damaged tabs on the
spool, worn ribs on the spool, missing spring,
broken ratchet wedges.
2.15. Replace the spool if it is worn or damaged.
NOTE: Bump knobs are a wearable item, and
are replaced in the course of normal use.
2.16. The housing is not fastened to the boom. It sim-
ply rests over a hexagonal drive collar.
See Figure 2.16.
Figure 2.13
Spring
Tab s
Ratchet wedges
Ribs
Figure 2.16
Drive collar
2.17. The ratchet wedges can be serviced by remov-
ing the three screws holding the black cover to
the top of the housing. See Figure 2.17.
2.18. Carefully remove the springs, and pull out the
wedges. See Figure 2.18.
Figure 2.17
Cover
Holes for screws
Small springs behind
Figure 2.18
Spring seats over
post on back of wedge
One rounded side,
insures correct orientation

McCulloch 32cc Trimmer
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2.19. When properly installed, the wedges should be
spring loaded. They retract when the ribs on the
back of the spool pass them, then extend to
keep the spool from rotating backwards.
See Figure 2.19.
3. RECOIL STARTER
3.1. Next to the cutting head, this is probably the
most common service item on the trimmer. It is
similar in principle to the MTDSW starter, but the
routing of the throttle and stop switch cables
necessitates a slightly different approach.
3.2. The throttle trigger, stop switch, and grip can all
be removed from the boom in unit with the
power-head. See Figure 3.2.
3.3. To separate the powerhead from the boom,
remove the screw at the top of the grip using a T-
25 driver, then withdraw the boom.
See Figure 3.3.
3.4. Remove the air filter cover using a T-25 driver to
gain access to the connection between the throt-
tle cable and the throttle arm on the carburetor.
See Figure 3.4.
Figure 2.19
Spring loaded
ratchet wedges
Figure 3.2
Screw holds grip
and Throttle housing
to boom
Positioning mark
Figure 3.3
grip slip off of boom
Trigger housing and
Screw
removed
Figure 3.4
Air filter
cover

McCulloch 32cc Trimmer
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3.5. Disconnect the throttle cable from the carburetor
by unhooking the Z-fitting at the carburetor end
of the cable. See Figure 3.5.
3.6. After the powerhead is separated from the
boom, and the throttle cable is slackened, the
housing that contains the stop switch and throttle
trigger can be separated from the grip.
NOTE: Alternatively, instead of removing the
complete powerhead and grip from the boom,
the clutch housing can be separated from the
starter housing. If this approach is taken, the
stop switch wires must be disconnected as the
two sections are separated. The throttle cable
will pull out of the starter housing and clutch
housing as the powerhead is removed. Because
of the difficulty of routing the throttle cable back
through the housings, a wire or string should be
connected to the z-fitting so that the throttle
cable can be “fished” back into place.
Figure 3.5
Z-fitting on end of
throttle cable
Throttle arm
on carburetor
3.7. Remove the two screws from the trigger housing
cover using a T-15 driver. See Figure 3.7.
3.8. Push the front part of the housing forward to
remove it. See Figure 3.8.
3.9. The throttle trigger will be released from its pivot
point, and the stop switch will remain with the
rear portion of the housing.
NOTE: The stop switch contacts two rub strips to
ground-out the ignition module. One rub strip is
connected to the primary windings of the mod-
ule, the other leads to ground.
Figure 3.7
Trigger housing
Trigger housing cover
Stop switch
Trigger housing
cover screws
Figure 3.8
Grip
slips out of grip
Trigger housing
Stop switch mounted
on cover plate
Stop switch
contacts

McCulloch 32cc Trimmer
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3.10. The trigger housing can be pulled-free of the grip
after the trigger and rear housing are removed.
See Figure 3.10.
NOTE: The throttle cable and stop switch wires
are held in adjacent channels by a white plastic
sleeve that is inserted in the grip.
3.11. Pull the white sleeve out of the grip and unplug
the stop switch wires from their connections to
the contact strips in the trigger housing.
See Figure 3.11.
3.12. The grip and clutch housing can be separated
from the engine by removing the four screws
that fasten them together, using a T-25 driver.
See Figure 3.12.
3.13. Remove the grip and clutch housing, and unplug
the stop switch wires from their connections on
the engine. See Figure 3.13.
NOTE: Pay attention to the routing of the throttle
cable and stop switch wires.
3.14. Disconnect the H.T. lead from the spark plug.
and remove the spark plug using an 5/8”
wrench.
3.15. Pack the cylinder full of starter rope to act as a
piston stop.
Figure 3.10
Channel for
stop switch wires
Channel for
throttle cable
White plastic
sleeve
Figure 3.11
Remove
sleeve
Figure 3.12
Clutch housing
Stop switch wires
Starter
housing
NOTE:The grip is
integral with the
clutch housing
Figure 3.13
Channel for stop
switch wires Channel for
throttle cable

McCulloch 32cc Trimmer
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3.16. Remove the clutch drum using a T-25 driver.
See Figure 3.16.
3.17. After the clutch drum is removed, the clutch rotor
can be removed using MTDSW clutch removal
tool # 791-180919. See Figure 3.17.
NOTE: a hammer and soft drift can be used if
the MTDSW tool is unavailable.
Figure 3.16
Clutch drum
Recoil rope used
as a piston stop
Figure 3.17
Crankshaft
Clutch rotor
Spade terminals
for stop switch wires
Throttle cable
3.18. The flat side of the clutch rotor seats against a
tube that surrounds the crankshaft.
See Figure 3.18.
3.19. With the clutch rotor removed, the starter hous-
ing can be removed.
3.20. Take out the four screws holding the starter
housing to the engine using a T-25 driver.
See Figure 3.20.
Figure 3.18
Flat side of clutch rotor
faces starter housing
Tube
Figure 3.20
Starter housing
Screws

McCulloch 32cc Trimmer
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3.21. Unplug the stop switch wires from the ignition
module as the starter housing is removed from
the engine. See Figure 3.21.
NOTE: There are two sets of stop switch wires.
The set inside the starter housing connects to
the ignition module. The set of stop switch wires
in the clutch housing connects the set inside the
starter housing to the stop switch.
3.22. The throttle cable is best left in the starter hous-
ing as it is removed. This can be done by simply
rotating the starter housing out of the way.
See Figure 3.22.
3.23. Alternatively, the throttle cable could be discon-
nected from the engine by squeezing the tabs,
and removing it along with the starter housing.
See Figure 3.23.
NOTE: If a throttle cable needs replacement,
attach a line to the carburetor end of the old
cable before removal, to facilitate “fishing” the
replacement cable into place.
3.24. Remove the baffle from the starter housing using
a T-25 driver.
NOTE: The starter pulley is held in place by the
baffle. There are no other fasteners on it.
3.25. Once the baffle is removed, the starter pulley
can be carefully lifted out to access the recoil
spring. See Figure 3.25.
Figure 3.21
Stop switch wires
Starter housing
Ignition module
Figure 3.22
Starter housing removed
Throttle cable
Figure 3.23
Squeeze tabs
Figure 3.25
Baffle
Posts
Stop
switch
wires