Horizontal Crankshaft


From small vehicles to water pumps, from generators to construction equipment, this engine gives solid power and efficiency.

Horizontal Crankshaft

Reliability meets Intelligence

GX660 Specifications
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Dimensions diagrams


Common model dimensions illustrated above. Model specific dimensions available in the "Downloads" menu.

Performance Curve



Engine Type Air-cooled 4-stroke OHV
Bore x Stroke 78 mm x 72 mm
Displacement 688 cm3
Net Power Output* 21.5 hp (16.0 kW) @ 3,600 rpm
Net Torque 35.6 lbs ft (48.3 Nm) @ 2,500 rpm
PTO Shaft Rotation Counterclockwise (from PTO shaft side)
Compression Ratio 9.3:1
Fuel Tank Capacity N/A
Lamp/Charge coil options 2.7A, 17A, 26A
Carburetor Horizontal type, two barrel butterfly valve, internal vent
Ignition System Digital CDI with variable ignition timing
Starting System Electric
Lubrication System Forced lubrication
Governor System Mechanical
Air Cleaner Dual element
Oil Capacity 1.9 litres (2.0 U.S. qts)
Fuel Unleaded 86 octane or higher
Dry Weight 44 kg (96.8 lbs)


Length (min) 405 mm (15.9")
Width (min) 410 mm (16.1")
Height (min) 438 mm (17.2")


A2 type N/A
AR type N/A
B type Straight shaft
D type Straight shaft
E type N/A
H type N/A
K type N/A
L type N/A
N1 type N/A
N5 type N/A
N7 type N/A
P type N/A
Q type N/A
R type N/A
S type Straight shaft (metric)
S3 type N/A
T type Straight shaft
V type Tapered shaft

*The power rating of the engine indicated in this document is the net power output tested on a production engine for the engine model and measured in accordance with SAE J1349 at 3,600 rpm (net power) and at 2,500 rpm (max net torque). Mass production engines may vary from this value. Actual power output for the engine installed in the final machine will vary depending on numerous factors, including the operating speed of the engine in application, environmental conditions, maintenance, and other variables.

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