GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual
© 2010 American Honda Motor Co., Inc — All Rights Reserved 1
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