Makita EK7651H, EK7650H User Manual

T

ECHNICAL INFORMATION

Models No. EK7650H, EK7651H

PRODUCT

P 1/ 19

Description

Power Cutters 305mm (12"), 355mm (14")

CONCEPT AND MAIN APPLICATIONS

Models EK7650H and EK7651H are the world’s first 4-stroke power cutters.
Their main features are:

• Low fuel consumption, low noise and clean exhaust emission achieved

by 4-stroke engine

• Easy start-up with Automatic decompression, Primer pump and

On/off choke combination switch with automatic half-throttle lock

• Low-vibration system with damper springs to absorb vibration from

engine to integrated front and rear handles.

Each wheel diameter is:
305mm (12") for model EK7650H
355mm (14") for model EK7651H

Specification

Specifications

Type
Displacement: cm³ (cu.in)

Engine

Engine oil

Fuel consumption: L/h (US oz/h)

Fuel tank capacity: L (US oz)

Starting

system

Wheel diameter:

Dry weight*2: kg (lbs)

*1 Some countries: E10 or E25 gasoline
*2 without cutting wheel

Fuel Straight unleaded gasoline*

Max. output: kW

Rapid start

(Spring-assisted recoil starter)

Decompression valve

mm (")

mm (")

EK7650H

in the class SF or higher of API Classification

305 (12)

97 (3-13/16)

Dimensions: mm (")

EK7650H

Length (L)

Width (W)

Height (H)

4-stroke

75.6 (4.6)

3.0 (at 7,500 min.

4.6 (at 5,500 min.

SAE10W-30 oil

1.7 (57.5)

1.1 (37.2)

No

Automatic (Mechanical)

435 (17-1/8) 455 (17-7/8)

ˉ¹)

ˉ¹)Max. torque: N.m

761 (30)

310 (12-1/4)

EK7651HModel

1

355 (14)

122 (4-13/16)Max. cutting depth:

12.9 (28.4)12.7 (28.0)

EK7651H

780 (30-3/4)

Standard equipment

Tool kit (Socket wrench 13-16, Hexalobular wrench, Slotted screwdriver and Tool bag)

Oil bottle (containing 220ml engine oil)
Water supply kit

Adapter ring (for some countries only)

Note: The standard equipment for the tool shown above may vary by country.

Optional accessories

Filter set
Trolley kit

Oil bottle set (10 bottles of 220ml engine oil)
Diamond wheel

Abrasive cut-off wheel

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Repair

CAUTION: Repair the machine in accordance with “Instruction manual” or “Safety instructions”.
Warning:

• Wear gloves.

• Remove the cutting tool from the unit.

• When the engine is hot from use, cool down the engine enough or you can get burned.

• Remove remaining fuel from Fuel tank and Carburetor completely. [FLAMMABLE MATERIAL KEEP FIRE AWAY]

• Remove Spark plug cap from Spark plug.

• Repair the engine on a stable workbench and in a clean workplace kept as free of dust and debris as possible.

• In order to avoid wrong reassembly, draw or write down where and how the parts are assembled, and what are the parts.

It is also recommended to have boxes ready to keep disassembled parts by group.

• Handle the disassembled parts carefully. Clean and wash them properly.

• If some bolts and screws are too tight, use Impact driver.

• Tighten the bolts and the screws to the specified torque as shown in "[5] Tightening torque specifications".

• Each time after you mounted a main part of the engine such as the piston, check if it moves smoothly

without abnormal noise by manually turning the crankshaft.

• After completion of reassembly, check for loose parts or abnormal noise and vibration
by manually turning the crankshaft.

[1] NECESSARY REPAIRING TOOLS

1R291

1R372

Follow the instructions described below in advance before repairing:

DescriptionCode No. Use for

Retaining ring pliers ST-2N for External ring1R003

Retaining ring pliers RT-2N for Internal ring1R005 removing Cotter

Torque wrench shaft 20-90N·m1R223

Ratchet head 12.7 (for 1R223)1R224

Hexalobular bit VT-27 (6.35mm)1R290

Retaining ring S and R pliers removing/ installing Retaining ring R-40

Retaining ring pliers1R311 removing Tubes

Flywheel puller1R364 removing Flywheel

Feeler gauge set1R366

Crank shaft lock bolt M10

Cotter removal attachment1R389 removing Exhaust / Intake valve system

Socket/ Socket bit 17--- removing/ installing Clutch

Socket/ Socket bit 24--- removing/ installing Clutch

Wire brush--- cleaning Spark plug

Hex wrench 2.5--- assembling/ removing / adjusting M5 Hex socket head bolt

Wrench 8--- holding M5x9 Hex nut

removing Lock off lever

press-fitting Ball bearing 6203LLU into Cutting deviceBearing setting pipe 25-17.21R030

assembling Clutch complete to Crankshaft

removing/ assembling CotterScrewdriver magnetizer1R288

removing/ assembling Hexalobular bolt

removing Pin 5 from Rocker arm assemblySpring pin extractor 4.01R308

adjusting the gap between Ignition coil and Flywheel,
Rocker arm assembly and Valve section, Spark plug

holding the position of Piston/ preventing Crankshaft from
being rotated

[2] GASKET

Once Gasket is removed:
(1) Clean up the mating surface where the gasket was installed to maintain its sealing performance.
(2) Replace it with a new one.

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Repair

[3] LUBRICANT/ ADHESIVE APPLICATION

Apply the following grease/ oil to protect parts and product from unusual abrasion.
Note: After assembly, supply 220cc of 4-cycle engine oil from the inlet of machine before trial run.
When disassembling the engine, put ThreeBond 1215 to the matching surface of Crank case and Cylinder block. (Fig. 66)

DescriptionItem No. Use for Amount

Retainer (2 pcs.)

109

Pin 5 Contact surface with the holes of Cylinder head assembly

112

Push rod (2 pcs.)

117

Exhaust valve

119

Intake valve

120

Cylinder block

123

complete

Cam lifter L

133

Cam lifter R

134

Oil seal 17

138

Crankshaft

140

complete

Oil seal L

185

Spiral spring Entire surface

208

Contact surface with 119 and 120

Contact surface with the holes of Rocker arm assembly

Contact surface with the inner periphery of Valve guide

Contact surface with Piston

• Contact surface with Push rod

• Contact surface with Cam gear complete

Inner periphery

• Steel balls in Ball bearings 6204LU and 6204

• Hole of Connection rod to pass Piston pin in Piston

• Needle cage in the other hole of Connection rod

Inner periphery

4-cycle Engine oil
(API grade SM class)

Makita grease N No. 2

4-cycle Engine oil
(API grade SM class)

Lubricant

a little

a little

a little

a littleMakita grease N No. 2

Fig. 1

134

133

Cylinder block complete

123

(It consists of Cylinder block
and Crankcase)

112

109

Valve
guide

117

Cylinder head
complete

119

120

Cylinder block

Crankcase

140

138

Connecting
rod

Ball bearing
6204LU

Starter assembly

185

Ball bearing
6204

208

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Repair

[4] DISASSEMBLY/ASSEMBLY
[4]-1. V-belt 5-800, Cutting device

DISASSEMBLING

(1) Loosen two M8 Hex nuts slightly with Wrench 13-16 of a standard accessory. (Fig. 2)
(2) Release the tension on V-belt 5-800 by turning M6 Tensioning screw counterclockwise with Screwdriver.
The position of M6 square nut shows the tension level; as it comes close to the minus mark, the belt tension is
relieved. (Fig. 2)
(3) When Water supply set is on the machine, remove it. (Fig. 3)
Holder (Fig. 2) can be removed from Belt cover by turning clockwise/ counterclockwise to 90° .
(4) Remove two M8 Hex nuts, then separate Belt cover and Hood section from the machine. (Fig. 4)
(5) When Hood section is disassembled:

1. Face the blade installation side of Spindle toward the ram of Arbor press.

2. Press Spindle out of Cutting device. Ball bearing 6203LLU is removed together with Spindle. (Fig. 5)
(6) Remove Retaining ring R-40 from Cutting device with 1R291, and then press the other 6203LLU out of
Cutting device. (Fig. 6)

Fig. 2 Fig. 3

Water supply set

M6 Square nut

Fig. 4

Cutting device

M8 Hex nut (2 pcs.)Minus mark

Hood section

V belt 5-800

Belt cover

M8 Hex nut

(2 pcs.)

Holder

Belt cover

M6 Tension screw

Fig. 5

Arbor press

Spindle

Cutting device

Note: Another Ball bearing 6203LLU
and Retaining ring R-40 are left
in Cutting device as drawn
in Fig. 6.

One of Ball bearing 6203LLU

Fig. 6

Cutting device viewed
from Belt cover side

Ball bearing
6203LLU

Retaining ring R-40

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Repair

[4] DISASSEMBLY/ASSEMBLY
[4]-1. V-belt 5-800, Cutting device (cont.)

ASSEMBLING

Assemble their parts by reversing the disassembly procedure.
(1) Assemble one of Ball bearing 6203LLU to Cutting holder, then snap Retaining ring R-40 into the groove of
Cutting device to secure the bearing.
(2) Insert Spindle into the other Ball bearing 6203LLU, then assemble them to Cutting device until they stop.
Note: Use two 1R030 as drawn in Fig. 7 so that their inner retainers of Ball bearings 6203LLU can be held without load
to the other portions.
This retains the proper tensions to their inner retainers.
(3) Insert Lock shaft into the place of Cutting device, then set Sliding disc and Impact plate. Push Lock shaft from
Belt cover side toward Blade installation side until the top bumps against Impact plate. (Fig. 8)
(4) Belt tension must be adjusted by turning M6 Tension screw clockwise until M6 Hex nut is aligned to a line between
plus mark and minus mark. (Fig. 9.)
(5) Holder of Water supply set can be set to Belt cover by turning clockwise/ counterclockwise to 90° .

Fig. 7

Fig. 8

[Belt cover side]

Fig. 9

M6 Square nut

1R030 to hold the inner retainer
of Ball bearing 6203LLU

1R030 to hold the inner retainer
of Ball bearing 6203LLU

Impact plate

Belt cover

Align the flat end of
Impact plate to that of
Hood complete.

Holder

Lock shaft

[Blade installation side]

Line

M6 Tension screw

Repair

[4] DISASSEMBLY/ASSEMBLY
[4]-2. Starter assembly

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DISASSEMBLING

(1) Loosen three M5x19 - Hexalobular socket head bolts, then remove
Starter assembly. (Fig. 10)
(2) When Starter rope is not broken;

1. Make a slack of Starter rope then hook it on U-shaped notch of Reel.
(Fig. 11)

2. Be sure to loosen the spiral spring force by turn Reel clockwise to spin
Starter rope around Reel before the step (3). (Fig. 11)
(3) Loosen M6x20 Set screw with Phillips screwdriver No. 3. (Fig. 11)
(4) When Reel is removed from Starter case, insert a index finger carefully to
the reverse side of Reel and then remove Reel from Starter case with
Spiral spring attached. (Fig. 12.)

Fig. 11

U-shaped
notch of Reel

Reel

Starter rope

Fig. 12

Starter case

Fig. 10

M5x19 - Hexalobular

socket head bolt

(3 pcs.)

Starter assembly (gray portion)

Hold Spiral spring
by an index finger.

Reel

M6x20 Set screw

ASSEMBLING

(1) If Spiral spring pops out of Reel, put it back in place by setting
the outer end of Spiral spring in place in Reel first, then by winding
Spiral spring counterclockwise towards the center of Reel. (Fig. 13)
(2) Apply a little amount of Makita grease N No.2 to the whole surface
of Spiral spring.
(3) Put Starter rope through Starter case complete.
After passing the one end through Starter knob and Rope stopper,
tie the end as drawn in Fig. 14. Then cover the top of Starter knob
with Cap.
After passing the other end from the hole of Starter case to Reel,
tie the end in Reel.
(4) Wind Starter rope around Reel for the 2/3 length (When the whole
length is 1m, wind 66cm.)
(5) While setting the inner end of Spiral spring into the center slot of
Starter case, assemble Reel to Starter case properly.
(6) Tighten M6x20 Set screw with Phillips screwdriver No. 3. (Fig. 11)
(7) Make a slack of Starter rope then hook it on U-shaped notch of
Reel. (Fig. 11) Turn Reel counterclockwise to spin Starter rope
around Reel.
Important: Make sure that the proper spring force is effective to Starter
assembly by turning Starter knob by hand and it can be
returned back to the original position. (Fig. 15)
Even if Starter rope is pulled to the full, there is room to
rotate Reel because of Spiral spring performance.

Fig. 13

Reel

Fig. 14

Fig. 15

Spiral spring

Set the outer end of
Spiral spring here.

Spiral spring

Cap

Rope stopper

Starter knob

Hole of Starter case