Makita UC3020A Manual

Model No.
Description
PRODUCT
CONCEPT AND MAIN APPLICATIONS
P 1 /10
Specification
Standard equipment
*Dimensions: mm (")
*Dimensions: excludes guide bar.
Width (W)
Height (H)
Length (L) 436
244
200
Note: The standard equipment for the tool shown above may differ by country.
UC3020A/ UC3520A/ UC4020A
Chain Saws 300mm (12")/ 350mm (14")/ 400mm (16")
H
L
W
Chain blade Pitch
Chain brake Mechanical brake
Chain oil tank capacity: ml
Chain speed per sec: m/s (m/min)
Standard guide bar: mm (")
Automatic chain oiling
Double insulation
Net weight: kg (lbs)
Power supply cord: m (ft)
Model No. UC3020A UC3520A UC4020A
13.3 (800)
0.3 (0.98)
3.8
(excluding guide bar and chain blade)
3/8"
200
Yes
Yes
400
(16)
300
(12)
350
(14)
Type 90SG-52E 90SG-56E90SG-46E
Chain blade ........................ 1 pc (UC3020A: 90SG-46E, UC3520A: 90SG-52E, UC4020A: 90SG-56E)
Guide bar ........................... 1 pc (UC3020A: 90SG 12", UC3520A: 90SG 14", UC4020A: 90SG 16")
Ghain cover ....................... 1 pc
Hook complete .................. 1 pc
These new electric chain saws have been developed as the
up-graded successors to the current UC3010A series models.
Designed with the concept of "Easy Operation and Maintenance",
and feature the following main advantages;
Toolless blade change and adjustment
Front grip ergonomically designed for high maneuverability
TECHNICAL INFORMATION
Continuous Rating (W)
Voltage (V) Cycle (Hz) Input Output Max. Output (W)
120
110 15 1,570
1,710
700 1,90050/ 60
8.6 1,800 1,000 2,40050/ 60
8.2 1,800 1,000 2,40050/ 60
7.9 1,800 1,000 2,40050/ 60
15 850 1,95050/ 60
220
230
240
Current (A)
Optional accessories
Chain blade (90SG, 91VG) (300/ 350/ 400mm)
Guide bar (90SG, 91VG) (300/ 350/ 400mm)
Chain oil

P 2 /10
Repair
[2] LUBRICATION
As illustrated in Fig. 1, to protect parts and product from unusual abrasion;
1) Apply Makita grease N. No.2 to the portions designated with the black triangle.
2) When replacing Oil pump complete, apply a little amount of Chain oil to the portions designated with the gray triangle.
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Lubricating Mechanism
Fig. 2
[1] NECESSARY REPAIRING TOOLS
CAUTION: Remove the chain blade, guide bar from the machine for safety before
repair/ maintenance ! Take off chain oil from oil tank !
1) Put the machine on a work bench as illustrated in Fig. 2, then separate Housing (R) from Housing (L) by removing
nine 4x18 Tapping screws.
Note: Housing (R) can be separated without removing Sprocket.
Important: Do not remove Oil tank cap in this step.
2) The parts marked with * and ** can now be replaced. (Fig. 2)
The parts marked with ** are components of lubricating mechanism.
DISASSEMBLING
*Brake switch
*O Ring 6 *Crank
O Ring 6 may be
removed together
with Housing (R)
in this step.
*Main switch *Power supply cord
Tapping screw
4x18 (9 pcs)
**Oil pump complete
Sprocket
**Oil tank
**Oil tube
**Oil tank cap
Housing (L)
Housing (R)
1R269 Bearing Extractor Removing ball bearings
DescriptionCode No. Use for
Bearing Box
Cam
Crank
Gear room (Apply about 3g.)
The portion that contacts 56 Crank
Pin portion that reciprocates in Oil pump complete
Spur gear 43
49
52
56
Oil pump complete
Fig. 1
Item No. Description Portion to lubricate
49
52
56

P 3 /10
Repair
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Lubricating Mechanism (cont.)
Fig. 4 Fig. 5
Fig. 6
Fig. 3
ASSEMBLING
1) Mount O ring 6 to the boss of Bearing holder. (Fig. 3)
2) See Fig. 4.
Before connecting Oil tube to Oil tank, make sure that:
1. Packing is mounted between Oil tank cap and Oil tank.
2. O ring 6 is mounted to Oil pump complete.
3. Clamp is put through Oil tube.
4. Cap and Spring are assembled to in Oil tube.
3) Push Oil tube into Oil tank deeply until it stops, and secure
with Clamp.
Note: Make sure that the tabs of Clamp is positioned on the
Housing (R) installation side as illustrated in Fig. 5.
Then connect the other end of Oil tube securely to Oil pump
complete.
4) Assemble the lubricating mechanism to the machine. (Fig. 6)
5) See Figs. 21 and 22 on page 10 for assembling of electrical
parts.
Oil tank cap
Packing
Oil tank
Cap
Spring
Oil tube
Oil pump complete O Ring 6
Clamp
tabs of Clamp
O Ring 6
Bearing holder
boss on Housing (L)
Route Oil tube as illustrated below.
Oil tube
pin of Crank
Oil pump complete
Crank
Housing (R)
installation side
Housing (L) side
boss
Oil tank
Oil tube
[A]
View from [A]
Insert pin of Crank into Oil pump complete.
boss on Housing (L)Oil tubeClamp
Oil pump complete

P 4 /10
Repair
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Lubricating Mechanism (cont.)
Fig. 7
If the oil is not supplied to chain or delivered very little;
1) Remove Guide bar, then Push nut and Filter. (Fig. 7) Run the machine without Filter.
If the oil flows out from Oil supply port, there is not trouble with Oil pump complete.
The malfunction is caused by clogged Filter in this case. Clean up Filter with kerosene.
2) If the oil does not flow out, remove Housing (R) (Fig.2on page 2) and disassemble Lubricating mechanism
(Fig.3on page 3), and check whether the following parts are clogged with foreign matter:
Filter in Oil tank, Oil tube, Oil pump complete
If clogged, remove foreign matter and clean up the part(s) with kerosene.
Reassemble Lubricating mechanism and Housing (R) to Housing (L), then Filter and Push nut to Housing (R).
Run the machine, then check whether the oil flows out.
3) If the oil does not flow out, the malfunction is caused by broken Oil pump complete.
Replace Oil pump complete with new one.
TROUBLE SHOOTING
Filter
Housing (R)
Important:
Removed Push nut can be reused.
However, replace with new one
if any one of the teeth is broken
or badly deformed.
Push nut
Oil supply port

P 5 /10
Repair
Fig. M-1
Fig. M-2 Fig. M-3
Fig. M-4
Refer to the explanation below when repairing Brake mechanism.
These models are equipped with the following two brake systems.
A. Brake Synchronized with Switch Lever
This brake works when Switch lever is released to stop operation. (Figs. M-1, M-2, M-3)
B. Kick Back Brake
This brake works when Front hand guard is pushed towards Chain bar. The machine stops even if Switch lever stays
in ON position. (Fig. M-4)
Principle of Brake Mechanism
[3] DISASSEMBLY/ASSEMBLY
[3] -2. Brake Mechanism and Armature
When Switch Lever is Pulled
Kick Back Brake
When Switch Lever is Released
Brake band is also pulled to unlock the drum portion
of Armature, and Armature starts rotating.
1) When Front hand guard is pushed towards Chain bar, Link plate complete is bent by the projection on the guard.
2) Brake band is pulled by the bent Link plate complete. (The tension force of Compression spring 9 keeps Link plate
complete bent.)
3) The drum portion of Armature is locked by Brake band to stop the rotation of Armature.
Brake band returns to the initial position to lock
the drum portion of Armature, and Armature immediately
stops rotating.
Link plate complete Brake band
Switch Lever
drum portion
of Armature
Compression spring 9
projection on
Front hand guard
projection on
Front hand guard
Link plate complete
Compression spring 9
Brake band
Brake band
Switch lever
Rod
Before Pulling Switch Lever
Switch lever
in ON position
drum portion
of Armature
drum portion of Armature
Brake mechanism viewed from the Housing (R) side

P 6 /10
Repair
[3] DISASSEMBLY/ASSEMBLY
[3] -2. Brake Mechanism and Armature
Fig. 11
DISASSEMBLING
Link plate
complete
Bearing holder
1) Remove Housing (R). (Fig.2on page 2)
2) Push Front hand guard towards the Guide bar installation side to lock Armature with kick back brake.
If Front hand guard is damaged, remove it and lock Armature by bending Link plate complete with a slotted
screwdriver. (Fig. 8)
3) Remove entire Lubricating mechanism (Oil pump complete, Oil tube, Oil tank). While swiveling Switch lever,
disconnect from Rod. Unscrew four 4x18 Tapping screws. (Fig. 9)
4) Put the machine as illustrated in Fig. 10. Remove Rear cover, then Carbon brush. The assembly of Armature and
Bearing holder can now be removed.
5) By hooking Rod on the notch of Bearing holder as illustrated in Fig. 11, place Rod in the same position as it would be
when Switch lever is pulled. Brake synchronized with Switch lever is now unlocked.
Housing (L)
Fig. 8 Fig. 9
Fig. 10
Armature
Bearing holder
Carbon brush
Rear cover
Tapping screw 4x18
Tapping screw
4x18 (4 pcs)
Oil tank
Switch lever
Rod
Oil tube
Oil pump complete
Push Link plate complete strong
using a slotted screwdriver.
Pull Rod in the direction of the arrow
and hook its bent portion on the notch
of Bearing holder.
notch of Bearing holder
Rod
Rod

P 7 /10
Repair
[3] DISASSEMBLY/ASSEMBLY
[3] -2. Brake Mechanism and Armature (cont.)
Fig. 12
Fig. 13
Fig. 15
DISASSEMBLING
6) Unlock the Kick back brake by pulling Link plate complete in the direction of the gray arrow with adjustable pliers.
(Fig. 12)
7) Armature can now be separated from Bearing holder as illustrated in Fig. 13.
8) Remove the tension force of Compression spring 9 from Link plate complete by pulling Link plate complete with
pliers in the direction of the gray arrow with adjustable pliers. (Fig. 14)
9) By removing Pin 5, Link plate complete and Compression spring 9 can be separated from Bearing holder. (Fig. 15)
Link plate complete
drum portion of Armature
Bearing Holder viewed form Armature Side
Hex nut M8
Spur gear 12
Bearing holder
Armature
Fig. 14
Link plate complete Compression spring 9
Brake band
Tapping screw 4x18,
securing Brake band
Brake ring
Link plate complete moves
in the direction of the black arrow.
Link plate complete moves
in the direction of the black arrow.
Brake band is loosened to unlock
the drum portion of Armature.
Brake band
Pin 5

P 8 /10
Repair
[3] DISASSEMBLY/ASSEMBLY
DISASSEMBLING
[3] -2. Brake Mechanism and Armature (cont.)
10) Remove Brake band by unscrewing Tapping screw 4x18, then disconnect Brake ring from Rod. (Fig. 16)
11) Remove Rod from Bearing holder. (Fig. 17)
Fig. 16 Fig. 17
Brake band
Bearing holder
Compression spring 5
Brake ring
Tapping screw 4x18
Flat washer 5
Rod
Take off rod from the slit by pulling in the direction
of Brake band installation side.
Rod
1) Assemble the components of Brake mechanism to
Bearing holder. (Figs. 17, 16, 15)
Note:
*Engage the notch on Brake band with the projection on
Brake ring when assembling Brake band to Bearing holder.
Otherwise Armature cannot be unlocked when Switch lever
is pulled for starting operation. (Fig. 18)
*Compression spring 9 of link plate complete has to be set
in the rib of bearing holder exactly. (Fig. 15 on page 7)
2) Unlock Kick back brake with pliers. (Fig. 12 on page 7)
3) Assemble Rod to Bearing holder as illustrated in Fig. 11 on page 6.
Kick back brake and brake synchronized with Switch lever are both unlocked in this step.
4) Assemble Armature to Bearing holder. (Fig. 13 on page 7)
5) Assemble Lubricating mechanism to Bearing holder. (Figs. 6, 5, 4, 3on page 3)
6) Pull Switch lever to loosen Brake band.
7) Engage Spur gear 43 mounted to Housing (R) with Spur gear 12 mounted to Armature.
Then turn Sprocket until Cam of Spindle fits in the loop portion of Crank.
8) Secure Housing (R) to Housing (L) with nine 4x18 Tapping screws. (Fig. 2 on page 3)
ASSEMBLING
Fig. 18
notch
projection
Brake band
Brake ring
Rod

Circuit diagram
P 9 /10
Black
White
Orange
Color index of lead wires' sheath
Brake switch
Front Grip SideRear Grip Side
Main Switch
Power SupplyCord
Field
Noise
suppressor
Rear Grip
Motor Housing
Front Grip
Fig. 19

Wiring diagram
P 10 /10
Fig. 20
(to main switch)
Field
Brake switch
A. Field Lead Wire (black)
Connecting lead wire (orange)
B. Field Lead Wire (white)
Lead wire holder
Lead wire holder
Lead Wire Holder
Rib F
Rib G
Rib D
Rib E
Rib C
Rib B
Rib A
Wall of
housing set (L) Recectaples
Top View of Bake Switch
The recectaples have to face the wall of
housing set (L).
A. Field Lead Wire (black) to Brake Switch
Route it between rib A and rib B.
B. Field Lead Wire (white) to main switch
Route it between rib C and rib D.
Route these lead wires between rib F and rib G, and then
put them into lead wire holders.
Motor Section
Handle Section
Main Switch
Noise Suppressor
Strain Relief
to Field
Power Supply Cord
Put noise suppressor into the space
between strain relief and main switch.
to Brake switch
Fig. 21