Honda GX240, GX270, GX340, GX390, UT2 Technical Manual

GX240

GX270

GX340

GX390

UT2/RT2

Technical Manual

©2010 American Honda Motor Co., Inc.	PTR54179
All Rights Reserved

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

Preface

This manual covers engine selection, engine installation design and engine installation testing, so the combination of a Honda engine and your equipment will make the best possible product.

Please feel free to contact your Honda Engine Distributor at any time for additional technical information or to discuss your engine application needs.

All information contained in this manual is based on the latest product information available at the time of printing. We reserve the right to make changes at anytime without notice.

No part of this publication may be reproduced, or transmitted, in any form or by any means, electronic, mechanical photocopying, recording or otherwise, without the prior written permission of the publisher. This includes text, figures and tables.

Contents
Design Features ..........................................................	2
Emission Regulations .................................................	2
Recommended Power Range .....................................	3
Maximum Operation ...............................................	3
Continuous Operation ............................................	3
Power Curve ..........................................................	3
Output Confirmation Methods ................................	5
Cooling .......................................................................	5
Minimum Cooling Air Flow Requirement ................	5
Ambient Temperature Limits ..................................	5
Testing ...................................................................	5
Engine Enclosures .................................................	6
Fuel System ................................................................	7
Fuel Tank Position .................................................	7
Fuel Line ................................................................	7
Fuel Valve Installation ............................................	7
Fuel Pump .............................................................	7
Fuel Tank Filter Installation ....................................	7
Controls .......................................................................	7
Engine Switch ........................................................	7
Carburetor Controls ...............................................	8
Exhaust System ..........................................................	9
Recommended Muffler ...........................................	9
Fabricated Exhaust Systems .................................	9
Engine Mounting .......................................................	10
Inclination .............................................................	10
Resonance Check ...............................................	10
Electrical System ......................................................	11
Battery ................................................................	11
Fuse .....................................................................	11
Engine Switch ......................................................	11
Charging Coil Selection .......................................	12
Lamp Coil Kit (optional) ........................................	12
Oil Alert® System (optional) ................................	12
Wiring Precautions ...............................................	12
Wiring Diagrams .......................................................	13
No Charge Coil Models ........................................	13
Electric Start Models ............................................	13
Power Transmission .................................................	15
V-Belt Connections ..............................................	15

Starting Performance ...........................................	16
Installation Considerations ........................................	17
Maintenance Points Accessibility ........................	17
Dimensional Drawings ...............................................	19
GX240-270 ...........................................................	19
GX340-390 ...........................................................	23
PTO Dimensional Drawings ......................................	27
H Type (with reduction) ........................................	27
L Type (with reduction) .........................................	27
P Type ..................................................................	28
Q Type ..................................................................	28
S Type ..................................................................	29
V Type ..................................................................	29
W Type .................................................................	30
Dimensions and Weights ...........................................	31
GX240 ..................................................................	31
GX270 ..................................................................	33
GX340 ..................................................................	34
GX390 ..................................................................	35
Specifications ............................................................	36
GX240 ..................................................................	36
GX270 ..................................................................	36
GX340 ..................................................................	37
GX390 ..................................................................	38
Serviceability .............................................................	39
Maintenance Schedule .........................................	39
Engine Oil Level Check ........................................	40
Engine Oil Change ...............................................	41
Air Cleaner Check/Cleaning and Replacement ....	41
Sediment Cup Cleaning .......................................	44
Spark Plug Check/Adjustment ..............................	45
Spark Plug Replacement ......................................	46
Spark Arrester Cleaning (if equipped) ..................	46
Idle Speed Check/Adjustment ..............................	47
Valve Clearance Check/Adjustment .....................	48
Combustion Chamber Cleaning ...........................	49
Fuel Tank and Filter Cleaning ..............................	50
Fuel Tube Check ..................................................	50
Evaporative emissions ...............................................	51
Types with OEM provided fuel tanks ....................	51

© 2010 American Honda Motor Co., Inc — All Rights Reserved

1

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

INTRODUCTION

Honda engines are designed for minimal maintenance. When maintenance is required, the task is kept simple by providing convenient maintenance access and procedures.

Honda engines use proven engine technology and design innovations to make them highly reliable engines.

DESIGN FEATURES

High Performance

OHV design reduces thermal distortion of the cylinder. This helps maintain the optimum seal between the piston rings and cylinder, which minimizes oil and fuel consumption. Power is also maintained in extreme operating conditions.

Smooth and Quiet Operation

OHV design provides a reduced reciprocating mass and balanced weight distribution. The 25° inclined cylinder produces a low center of gravity for the moving parts, which further reduces vibration for quiet operation. These features, and the compact design result in extremely smooth operation.

Use of proven design technologies reduces noise from internal engine components. The hardness of reciprocating parts, the helical cut gears on the crankshaft and camshaft and the use of select materials makes these engines exceptionally quiet. The large muffler is designed to further reduce noise.

Durability/Reliability

Honda engines are built with quality that provides proven durability and reliability. Proven features such as OHV design and cast iron cylinder sleeve provide long life in all types of operating conditions. To further enhance the reliability of these engines, a 2-stage air cleaner system, digital electronic ignition system, mechanical centrifugal governor and proven side-draft carburetor are standard features.

EMISSION REGULATIONS

The Honda GX390 engines meet U.S. Environmental Protection Agency and the California Air Resources Board regulations.

Honda engine distributors and equipment manufacturers that use Honda engines are required by regulation to follow this OEM technical manual. Correct engine matching ensures that the engine will be durable (and emission durable) in use.

2	© 2010 American Honda Motor Co., Inc — All Rights Reserved

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

RECOMMENDED POWER RANGE

Maximum Operation

Operate the engine at not more than 90% of the maximum horsepower available at a given rpm.

Recommended maximum operating hp = 0.9 x maximum hp

Continuous Operation

For continuous operation (more than 30 minutes), operate the engine at not more than 80% of the maximum horsepower available at a given rpm.

Continuous recommended operating hp = 0.8 x maximum hp

Power Curve

GX240

	(N·m)																(lbf·ft)						(kgf·m)
	20												15										2.0
																						14
<![if ! IE]> <![endif]>TORQUE																													1.9
	16																12
	18																					13							1.8
							NET TORQUE
																														1.7
																	11													1.6
	14																						1.5
	(KW)
	7																(HP)						(PS)
																	9						9
	6
																	8												8
								NET POWER
<![if ! IE]> <![endif]>OUTPUT	5																				7								7
																	6
																							6
	4																				5								5
	3
																	4						4
						RECOMMENDED OPERATING SPEED RANGE
	2
	2000						3000						3600
								ENGINE SPEED (rpm)

GX270

	(N·m)														(lbf·ft)					(kgf·m)
	20											15
																			14	2.0
<![if ! IE]> <![endif]>TORQUE																									1.9
	16														12
	18																		13						1.8
							NET TORQUE
																									1.7
															11										1.6
	14																			1.5
	(KW)
	7														(HP)					(PS)
															9					9
	6
															8										8
						NET POWER
<![if ! IE]> <![endif]>OUTPUT	5																		7						7
															6
																				6
	4																		5						5
	3
															4					4
					RECOMMENDED OPERATING SPEED RANGE
	2
	2000					3000						3600
							ENGINE SPEED (rpm)

© 2010 American Honda Motor Co., Inc — All Rights Reserved

3

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

GX340

GX390

<![if ! IE]>

<![endif]>TORQUE

<![if ! IE]>

<![endif]>OUTPUT

(N·m)
28															(lbf·ft)
26															20
																				19
24							NET TORQUE													18
																				17
22
																				16
20															15
(KW)															(HP)
9															12
8																					11
						NET POWER
7																					10
																					9
6
																					8
5																					7
															6
					RECOMMENDED OPERATING SPEED RANGE
4
2000						3000						3600
							ENGINE SPEED (rpm)

(kgf·m)

2.8

2.7

2.6

2.5

2.4

2.3

2.2

(PS)

12

11

10

9

8

7

6

<![if ! IE]>

<![endif]>TORQUE

<![if ! IE]>

<![endif]>OUTPUT

(N·m)												(lbf·ft)			(kgf·m)
28
														21
														20				2.8
26																		2.7
														19
																		2.6
						NET TORQUE
24														18				2.5
														17				2.4
22														16				2.3
																		2.2
20														15
(KW)												(HP)
9														12
8
														11
					NET POWER
7														10
														9

6 8

7

5

6

RECOMMENDED OPERATING SPEED RANGE

4

2000

3000

3600 (min-1 [TRO])

ENGINE SPEED

4	© 2010 American Honda Motor Co., Inc — All Rights Reserved

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

Output Confirmation Methods

Governor Rod Measurement

When the engine is properly matched and operating at its continuous rated load, the carburetor throttle angle should be approximately half way between full open and full closed positions.

Bring the engine to normal operating temperature and then apply the expected continuous load. If the throttle is more than halfway open, the engine is being overloaded resulting in overheating and shortened engine life.

Tachometer RPM Measurement

Normal governor droop can also be used to measure engine load.

At rated speed:	(	rpm with load	)
	1-			100% ≤ 5%
		rpm without load

Engine is operating within the continuous recommended power range.

COOLING

Minimum Cooling Air Flow Requirement

Engine enclosure must have the minimum cooling air flow listed below.

GX240/GX270: 7 m3 (247 ft3) per minute at 3,600 rpm

GX340/GX390: 8 m3 (282 ft3) per minute at 3,600 rpm

Ambient Temperature Limits

-15 to +40°C (+5 to +104°F)

Testing

•Use thermocouple temperature probes at the specified locations.

•Operate the engine under worst-case conditions

•An electronic data logger is required for the temperature data collection

•Set up the data logger to take multiple readings per minute. If data is being taken manually, a reading every 5 minutes is adequate.

•Take readings until the engine oil temperature is stabilized at continuous rated load

•Run the application for one hour of continuous operation; the temperatures should be stabilized in that time. If the application is used only for short intervals, note the normal run time in the application document.

•Shut the engine down and continue to take readings. Attempt to restart the engine after heat soaking for 5 minutes.

•For enclosed applications, fuel bowl temperature should be monitored after testing until the maximum is reached - this may take several minutes

© 2010 American Honda Motor Co., Inc — All Rights Reserved

5

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

Maximum Operating Temperatures

Spark plug Seat	270 °C (482 °F)
Engine Oil	140 °C (284 °F)
Gasoline at Carburetor Float Bowl	60 °C (140 °F)
Gasoline at Carburetor Float Bowl (after 5 min. hot soak)	<70 °C (158 °F)
Gasoline at Fuel Tank	60 °C (140 °F)

These temperatures are based on an ambient temperature of 40°C (104°F). Compensate for any deviation linearly; i.e., if the ambient temperature is 20°C (68°F), the maximum acceptable oil temperature is 120°C (248°F).

Adjusted oil temperatures of less than 40°C will require more frequent oil changes.

Engine Enclosures

When the engine installation in the equipment obscures the emission label, a duplicate label must be applied. In this case, as part of the engine matching process, it will be necessary to establish a process for the OEM to obtain duplicate labels. EPA requires full documentation, control, and record keeping of the duplicate label process.

Cool Air Intake

The engine must be provided with a cooling duct so that fresh air can be drawn directly from outside the enclosure cover. Install the cooling air duct with the intake port in a place free from dust and dirt. The cooling air volume changes according to the shape of the duct and screen and the engine installation conditions. Operate the engine under the normal operating conditions and be sure that the engine meets all temperature requirements.

The cooling air duct must have a cross-sectional area of at least 300 cm2 (46.5 sq in).

When the engine is operated in dusty areas, install a filter at the enclosure inlet for the cooling air. This will reduce the effective area, so you must increase the size of the inlet accordingly. Increase the size of the inlet to the point where the maximum operating temperatures are not exceeded when operated under maximum load.

Install the cooling air duct and filter so that the filter can be easily checked, and dust, dirt and foreign material removed.

Hot Air Discharge

Hot air must be discharged directly outside the enclosure. Provide a discharge duct if necessary. The minimum cross section of the hot air discharge opening must be larger than that of the cooling air inlet.

Locate the discharge port so the hot discharge air does not flow back into the enclosure. Provide sufficient ventilation to prevent the engine compartment temperature from rising above ambient temperature limits after the engine has been stopped.

Exhaust Discharge

The exhaust system becomes hot during operation and remains hot for a while after operation. Separate the exhaust system from the engine compartment with a partition wall and locate the exhaust system in the discharged cooling air flow.

Be sure the exhaust gas is directly discharged outside the enclosure without being blocked or restricted by any obstacles. The exhaust gas must not flow back or be drawn back into the enclosure.

Provide the engine with an exhaust deflector or exhaust pipe extension if necessary. If an extension pipe is used:

•Keep the length of the pipe as short as possible to keep exhaust backpressure within limits (see page 10).

•The extension pipe must have an ID larger than the OD of the muffler outlet.

•Verify the exhaust pipe extension does not create excessive vibration at any given engine rpm. If necessary, use an exhaust pipe holder to support the exhaust pipe extension.

Grass Cutting Applications

When the engine is operated on grass cutting equipment, install a rotary screen grid on the cooling air intake port to prevent the accumulation of large clippings.

Do not allow the grass clippings shredded by the rotary screen grid to accumulate around the intake port.

6	© 2010 American Honda Motor Co., Inc — All Rights Reserved

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

FUEL SYSTEM

If the engine is supplied with an incomplete fuel system (no fuel tank, no fuel hose, etc.), the OEM is responsible for ensuring evaporative emission requirements/regulations are met, including certification.

Fuel Tank Position

If a remote fuel tank is used, it must be installed so that its maximum gasoline level is within 50 cm (19.5 in) above the carburetor gasoline level. If a fuel pump is used, the maximum fuel level should be within 50 cm (19.5 in) above or below the carburetor gasoline level.

Fuel Line

Use a low permeation fuel line (displaying an Executive Order number) rated for use with gasoline. The fuel line should have an inside dimension of 5.5 mm (0.22 in). Keep the fuel line as short as possible. Install the fuel line so it will not rest against any sharp objects or make sharp bends that can restrict the flow of fuel. If the fuel line passes through an enclosure wall, protect the line with a rubber grommet. Route the fuel line away from hot engine and exhaust system components and away from electrical wiring. Secure the fuel line to prevent sagging and bending.

Fuel Valve Installation

If a remote fuel tank is used, a fuel valve should be installed so it is easily accessible. Install the fuel valve at the outlet of the fuel tank and use an easily read label to indicate valve location and operation. If under the fuel tank is not the ideal location, securely install the fuel valve in-line with the fuel tube in a cool location, so that engine heat cannot cause vapor lock.

Fuel Pump

A fuel pump should be selected that provides a maximum operating pressure of 0.1 kgf/cm2 (1.4 psi) and delivers 15 liters/hr (4.0 US gal/hr). If a secondary fuel pump is used, to prevent carburetor flooding, its operating pressure must not exceed the standard fuel pump’s operating pressure.

Fuel Tank Filter Installation

It is recommended that a fuel tank strainer with a mesh rating of #80 be installed at the fuel tank inlet to catch debris when refueling. It is also recommended that a fuel tank sump be provided at the fuel tank outlet to reduce the chance of contaminants entering the fuel system.

CONTROLS

Engine Switch

Use a three-position engine switch with continuity between its terminals as shown.

Wire Color

EXT+

EXT –

ST

BAT

(Red)

(Black)

(Black/White)

(White)

Switch Position

OFF

ON

{

{

START

{

{

{

{

© 2010 American Honda Motor Co., Inc — All Rights Reserved

7

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

Carburetor Controls

Types of cable:

Two types can be used, flexible wire core or solid wire.

Installation:

The throttle and choke control levers are provided with holes for optional cable attachment. The following illustrations show installation examples for a solid wire cable and for a flexible, braided wire cable. If using a flexible, braided wire cable, add a return spring as shown. It is necessary to loosen the throttle lever friction nut when operating the throttle with a remote-mounted control.

Remote Control Throttle

THROTTLE LEVER

FRICTION NUT

Flexible wire core mounting

		4 mm SCREW
	WIRE	WIRE HOLDER OPTIONAL
	5 mm	THROTTLE
		LEVER
	CIRCLIP
	Solid wire core
	mounting

Remote Control Choke.

4 mm SCREW WIRE HOLDER

SPRING

WIRE

5 mm CIRCLIP

8	© 2010 American Honda Motor Co., Inc — All Rights Reserved

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

EXHAUST SYSTEM

Recommended Muffler

The recommended muffler and exhaust pipe are matched to the engine in terms of emissions performance, exhaust backpressure, sound level, and durability.

Consider the following:

•Discharge the exhaust gas directly to the open air. Do not install flammable parts or any parts with poor heat resistance properties around the exhaust system or near the discharge port.

•The exhaust gas must not enter the cooling-air intake port. Be especially careful when using the exhaust deflector to change the discharge direction.

•The muffler and exhaust pipe become very hot during operation and remain hot after the engine has been shut off. Install the muffler and exhaust pipe so the fuel system and other heat-sensitive components are isolated from the exhaust heat.

Fabricated Exhaust Systems

The muffler type and the shape and length of the exhaust pipe(s) affect emissions performance and engine power. If you use a muffler other than a recommended Honda muffler, observe the following precautions to maintain the engine’s peak performance:

•The shape (bends and elbows) of the exhaust pipe can affect exhaust backpressure. If exhaust backpressure is excessive, it can affect emissions performance and/or cause detonation.

•The exhaust pipe inside diameter must be the same size as the exhaust port diameter.There must be no gap between the port inside diameter and the exhaust pipe ID.

•The exhaust backpressure increases if the diameter is less than specified. If the diameter is larger than specified, the effective width of the exhaust gasket is reduced which could cause an exhaust leak.

•When the exhaust pipes are connected together before the muffler, make sure that the exhaust pipe length is as short as possible to reduce backpressure.

•Muffler volume and design will affect exhaust backpressure. Increase the volume of the muffler if exhaust backpressure is higher than specified.

Exhaust Back Pressure Measurement

Measure the exhaust back pressure at the exhaust pipe with the engine under continuous load (WOT), 30 mm (1.2 in) from the exhaust pipe mounting flange as shown (make sure the test nipple does not extend beyond the inner wall of the exhaust pipe).

		3000 rpm		3600 rpm
		Min.	Max	Min.	Max
GX240	kPa	4.2	9.0	4.9	11.0
GX270	mmH2O	428	918	500	1122
GX340	kPa	4.6	10.5	6	12.5
GX390	mmH2O	469	1071	612	1275

© 2010 American Honda Motor Co., Inc — All Rights Reserved

9

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

Rigid Engine Mount Muffler Installation.

The frame must be rigid to prevent cracking when the exhaust pipe and muffler are connected. The muffler should be installed securely with bolts and nuts.

The muffler should be supported at two points (or more) using special rubber mounts designed for muffler support applications.

Check to see muffler vibration does not increase at any given engine speed, causing an abnormal increase in resonance.

Rubber Engine Mount Muffler Installation

A flexible pipe should be used between the muffler and exhaust pipe when the engine is mounted to the engine bed with rubber mounts. The flexible pipe ID must be the same as the exhaust pipe OD or larger.

The muffler should be supported at two points (or more) and should be installed securely with bolts and nuts to prevent muffler cracking from vibration during starting and stopping.

Check to see muffler vibration does not increase at any given engine speed, causing an abnormal increase in resonance.

ENGINE MOUNTING

Use an engine bed or frame with enough rigidity to allow maximum durability of the engine and attachment installation.

The engine must not wobble on the engine bed. Use an engine bed or frame that provides a flat surface for the engine to be mounted on. If there is a gap between the engine and the engine bed, the engine-mounting surface may be damaged.

Inclination

Horizontal mounting and operation of the engine is recommended. If the engine must be operated on a slope, the incline position of the engine must not exceed 20° in any direction.

Resonance Check

There must be no resonance when the engine and attachment are operated within the designated speed range. Slowly raise the engine speed from idle to maximum and check for resonance at any engine speed.

General Methods for Preventing Resonance

When engine accessories or a part of the attachment is resonating, increase the rigidity of the resonating part to bring the resonance point higher than the working engine speed range.

•Increase the rigidity of the engine bed and frame to bring the resonance point higher than the working engine speed range.

•Install the muffler on the engine body, using a rigid stay to prevent resonance of the muffler when the engine speed is within the specific operating speed range.

10	© 2010 American Honda Motor Co., Inc — All Rights Reserved

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

Engine Acceleration/Vibration

Using a vibration meter, measure the vibration amplitude at the base on three axis (vertical, lateral and horizontal).

Direction	Allowable G value
	(Peak)	(RMS)
Vertical	10 (98 m/s2)	6.9 (68 m/s2)
Horizontal	5.9 (58 m/s2)	4.2 (41 m/s2)
Lateral	6.9 (68 m/s2)	4.9 (48 m/s2)	LATERAL

ELECTRICAL SYSTEM

<![if ! IE]>

<![endif]>VERTICAL

HORIZONTAL

Battery

Use a 12 V battery with a minimum capacity of 24AH.

Fuse

Recommended fuse size:	Charging system (A)	Fuse (A)
	1.0	5
	3.0	15
	10.0
	18.0	25
Battery Cables

Select battery cables to avoid greater than 0.5 volt drop in the cable during starter motor operation.

Battery cable size and length: (Gauge x Length)

Positive cable: AWG No. 4 x 1.5 m (5.0 ft) maximum Negative cable: AWG No. 4 x 2.3 m (7.5 ft) maximum

Engine Switch

Electric start

Use a three-position engine switch with continuity between its terminals as shown.

Wire Color

EXT+

EXT –

ST

BAT

(Red)

(Black)

(Black/White)

(White)

Switch Position

OFF

ON

{

{

START

{

{

{

{

Vdc/A (rated)

AC300V, 220mA (PEAK)

12/15A

Dia. (recommended)

AV0.5

AV0.5

AV2.0*

AV0.75

* In combination with 1A/3A/10A charge coil, AV1.25 is acceptable. AV0.5 = Automotive Vinyl, 0.5 mm2 cross-sectional area

Do not run the starter motor for more than 5 seconds at a time. Always allow resting for 10 seconds before each starting attempt.

© 2010 American Honda Motor Co., Inc — All Rights Reserved

11

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

Manual start

Use a two-position engine switch with continuity between its terminals as shown.

Wire Color	EXT+		EXT –
Switch Position	(Red)		(Black)
OFF
ON	{			{

Charging Coil Selection

Four types of coils are available:

	Coil	Output (A)	Regulated	RPM
	1A	0.9	No
	3A	2.7	No	3,600
	10A	9.5	Yes
	18A	17.0	Yes

The 1A and 3A coils are only suitable for recharging a starting battery. Use the 10A or 18A coils when powering accessories.

Lamp Coil Kit (optional)

Three types of lamp coils are available: 6v –25w, 12v –15w, 12v –25w. Two coils can be installed in parallel to provide 12V-50W, if no charging coils are applied. Use parallel connector (No. 32105-ZE1-000) to connect two coils in parallel. A single coil (12v-25w) can be used in combination with the 3A charge coil as required.

Oil Alert® System (optional)

The Oil Alert System uses a float type switch located inside the crankcase. When the engine oil level falls below a safe operating level, the float falls and the circuit is completed through the control box, grounding the primary side of the ignition coil. The Oil Alert System is only recommended for use on equipment that is stationary while operating.

Wiring Precautions

•Connect the battery positive (+) cable to the positive terminal of the starter solenoid.

•Connect the battery negative (–) cable to the engine crankcase or engine frame mounting bolt.

•Do not route the battery cables on or near any hot, moving, or rotating parts, or sharp edges. Keep the battery cables and electrical wires away from the fuel line.

•Protect positive electrical connections with a cover or insulation.

12	© 2010 American Honda Motor Co., Inc — All Rights Reserved

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

WIRING DIAGRAMS

No Charge Coil Models

C3	C1
	C2

<![if ! IE]> <![endif]>Y

<![if ! IE]> <![endif]>Y

<![if ! IE]> <![endif]>Bl

<![if ! IE]> <![endif]>R

<![if ! IE]> <![endif]>R

<![if ! IE]> <![endif]>Bl

1

ENGINE STOP SWITCH

EXT ( + )

EXT ( - )

4

3

1

2

<![if ! IE]> <![endif]>LED

<![if ! IE]> <![endif]>ALTOIL

<![if ! IE]> <![endif]>EXT( - )

<![if ! IE]> <![endif]>EXT( + )

OFF

ON

Bl

Black

Br

Brown

Y

Yellow

O

Orange

ENGINE STOP

Bu

Blue

Lb

Light blue

SWITCH

G

Green

Lg

Light green

R

Red

P

Pink

W

White

Gr

Gray

OIL LEVEL

SPARK

IGNITION

TWO

COLORED

WIRE (EXAMPLE:YELLOW/RED)

SWITCH

PLUG

COIL

Electric Start Models

18A Charging System

C3

<![if ! IE]> <![endif]>Y

<![if ! IE]> <![endif]>Y

<![if ! IE]> <![endif]>Bl

<![if ! IE]> <![endif]>R

1

4

3

1

2

<![if ! IE]> <![endif]>LED

<![if ! IE]> <![endif]>OIL ALT

<![if ! IE]> <![endif]>EXT ( - )

<![if ! IE]> <![endif]>EXT ( + )

OIL LEVEL	SPARK	IGNITION
SWITCH	PLUG	COIL
	COMBINATION
	SWITCH
EXT ( + ) EXT ( - )		ST	BAT
OFF
ON
START

C10

CONTROL BOX

(W)

(W)

<![if ! IE]> <![endif]>W

MAIN FUSE

<![if ! IE]> <![endif]>W

C1

Bl

Bl

R

R

C2

Bl

<![if ! IE]> <![endif]>Gr

<![if ! IE]> <![endif]>Gr

C11

<![if ! IE]> <![endif]>Gr

<![if ! IE]> <![endif]>Gr

<![if ! IE]> <![endif]>W

<![if ! IE]> <![endif]>W

<![if ! IE]> <![endif]>Bl

<![if ! IE]> <![endif]>(W )

<![if ! IE]> <![endif]>Bl/W )

C8

C9

<![if ! IE]> <![endif]>(

3

T1

C4

CHARGE

COIL

4

6

1

2

3

5

<![if ! IE]> <![endif]>( Bl )

<![if ! IE]> <![endif]>Bl/W

<![if ! IE]> <![endif]>Gr

<![if ! IE]> <![endif]>Gr

<![if ! IE]> <![endif]>R

<![if ! IE]> <![endif]>Bl

<![if ! IE]> <![endif]>W

<![if ! IE]> <![endif]>W/Bu

T2

<![if ! IE]> <![endif]>Gr

<![if ! IE]> <![endif]>Gr

<![if ! IE]> <![endif]>Bl/Y

<![if ! IE]> <![endif]>W

<![if ! IE]> <![endif]>Bl

T4

<![if ! IE]> <![endif]>ST

<![if ! IE]> <![endif]>EXT ( + )

<![if ! IE]> <![endif]>EXT ( - )

<![if ! IE]> <![endif]>BAT

T3

FLYWHEEL

COMBINATION

SWITCH

REGULATOR/

BATTERY

STARTER MOTOR

CHARGE

RECTIFIER

COIL

Bl	Black				Br	Brown
Y	Yellow				O	Orange
Bu	Blue				Lb	Light blue
G	Green				Lg	Light green
R	Red				P	Pink
W	White				Gr	Gray

TWO COLORED WIRE (EXAMPLE:YELLOW/RED)

© 2010 American Honda Motor Co., Inc — All Rights Reserved

13

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

10A Charging System

C3

<![if ! IE]> <![endif]>Y

<![if ! IE]> <![endif]>Y

<![if ! IE]> <![endif]>Bl

<![if ! IE]> <![endif]>R

1

4

3

1

2

<![if ! IE]> <![endif]>LED

<![if ! IE]> <![endif]>OIL ALT

<![if ! IE]> <![endif]>EXT ( - )

<![if ! IE]> <![endif]>EXT ( + )

OIL LEVEL	SPARK	IGNITION
SWITCH	PLUG	COIL
	COMBINATION
	SWITCH
EXT ( + ) EXT ( - )		ST	BAT
OFF
ON
START

C1

Bl

Bl

R	R
	C2

<![if ! IE]> <![endif]>W	<![if ! IE]> <![endif]>Gr
	4
1	2
<![if ! IE]> <![endif]>W	<![if ! IE]> <![endif]>Gr

FLYWHEEL

CHARGE COIL

CONTROL BOX

C10

(W)

(W)

<![if ! IE]>

<![endif]>W

MAIN FUSE

<![if ! IE]>

<![endif]>W

						Bl
						C11
<![if ! IE]> <![endif]>Gr	<![if ! IE]> <![endif]>W	<![if ! IE]> <![endif]>W	<![if ! IE]> <![endif]>W	<![if ! IE]> <![endif]>Bl	<![if ! IE]> <![endif]>( W )	<![if ! IE]> <![endif]>Bl/W )
						<![if ! IE]> <![endif]>(
					3	C4
					T1
4	6	1	2	3	5	<![if ! IE]> <![endif]>( Bl )	<![if ! IE]> <![endif]>Bl/W	<![if ! IE]> <![endif]>R	<![if ! IE]> <![endif]>Bl	<![if ! IE]> <![endif]>W
		<![if ! IE]> <![endif]>Bl/Y			T2
<![if ! IE]> <![endif]>Gr	<![if ! IE]> <![endif]>Gr		<![if ! IE]> <![endif]>W	<![if ! IE]> <![endif]>Bl	<![if ! IE]> <![endif]>W/Bu		T4
							<![if ! IE]> <![endif]>ST	<![if ! IE]> <![endif]>EXT ( + )	<![if ! IE]> <![endif]>EXT ( - )	<![if ! IE]> <![endif]>BAT
					T3
							COMBINATION
								SWITCH

REGULATOR/	BATTERY	STARTER MOTOR
RECTIFIER

Bl	Black				Br	Brown
Y	Yellow				O	Orange
Bu	Blue				Lb	Light blue
G	Green				Lg	Light green
R	Red				P	Pink
W	White				Gr	Gray

TWO COLORED WIRE (EXAMPLE:YELLOW/RED)

14	© 2010 American Honda Motor Co., Inc — All Rights Reserved

GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual

1A/3A Charging System

CONTROL BOX

C1

( Bl )					( Bl )

C3					C2
				( R )	( R )
					C5
				W	Gr
				<![if ! IE]> <![endif]>( W )	<![if ! IE]> <![endif]>Bl/W )
<![if ! IE]> <![endif]>( Y )					<![if ! IE]> <![endif]>(
		<![if ! IE]> <![endif]>Y	<![if ! IE]> <![endif]>Bl	<![if ! IE]> <![endif]>R	C4
					T1
				1
				T2
4	3	1		2	<![if ! IE]> <![endif]>)	<![if ! IE]> <![endif]>)
<![if ! IE]> <![endif]>LED		<![if ! IE]> <![endif]>OIL ALT	<![if ! IE]> <![endif]>EXT ( - )	<![if ! IE]> <![endif]>EXT ( + )	<![if ! IE]> <![endif]>( W	<![if ! IE]> <![endif]>( W

T3	MAIN FUSE

OIL LEVEL

SPARK

IGNITION

CHARGE

BATTERY

STARTER MOTOR

SWITCH

PLUG

COIL

COIL

COMBINATION

SWITCH

EXT ( + )

EXT ( - )

ST

BAT

OFF

ON

START

<![if ! IE]> <![endif]>( W )

<![if ! IE]> <![endif]>( W )

<![if ! IE]> <![endif]>( W )

<![if ! IE]> <![endif]>( Gr )

<![if ! IE]> <![endif]>Bl/W )

<![if ! IE]> <![endif]>( R )

<![if ! IE]> <![endif]>( Bl )

<![if ! IE]> <![endif]>( W )

2

<![if ! IE]> <![endif]>(

C6	C7
	2	1
		<![if ! IE]> <![endif]>ST	<![if ! IE]> <![endif]>EXT ( + )	<![if ! IE]> <![endif]>EXT ( - )	<![if ! IE]> <![endif]>BAT
CIRCUIT		SILICON

PROTECTOR

RECTIFIER

COMBINATION

SWITCH

Bl

Black

Br

Brown

Y

Yellow

O

Orange

Bu

Blue

Lb

Light blue

G

Green

Lg

Light green

R

Red

P

Pink

W

White

Gr

Gray

TWO

COLORED

WIRE (EXAMPLE:YELLOW/RED)

© 2010 American Honda Motor Co., Inc — All Rights Reserved

15