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Honda GX630 Gas Engine Electric start 1" straight side shaft GX630RH-QZB3 GX630-QZB3

Price: $2,693.00
Sale Price: $1,899.00
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97.00 LBS
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Prop. 65 Warning: This product contains chemicals known to the state of California to cause cancer and birth defects, or other reproductive harm.





Honda GX630RH-QZB3 GX630-QZB3 Gas Engine Electric Start

688cc 20.8HP With 1" Diameter, 1/4" Keyway Horizontal Shaft

The highest quality guaranteed! We have been in business since 2005, and our engines are fully rebuildable with all parts available. The Honda GX630 engine replacement for GX630RH-QZB3 or GX630-QZB3.
* Please note that free shipping does not apply to CA, WA, AZ, or OR NV.  Please contact us for a rate.  Thank you.
The Honda GX630 is the go-to engine for go karts, generators, pressure washers, and various industrial and commercial uses. These premium residential motors are fuel efficient, easy starting and smooth performance. This convenient, heavy duty and reliable 4 stroke OHV twin cylinder engine does the job for many applications. Also, offering a 3-year limited warrenty on these motors. Your order ships quickly with expert turnaround time in our fully stocked warehouse. Packaged with care, Carroll Stream Motor Company provides free shipping.

This Honda engine is a 4 Stroke OHV twin cylinder, which is a 88 X 64 stroke. It is a 688cc, 20.8 HP and 3600 RPM.

This Honda small motor is built with quality components and is ready to outlast the competition. Purchase now to take advantage of our free shipping and quick turnaround time. Or, call if you have questions! 888-208-2088, 248-628-4638.

Summary of the GX630

The Honda GX630RH-QZB3 is a powerful and reliable gas engine manufactured by Honda, known for its durability, performance, and versatility. The GX630 is a horizontal shaft, V-twin, 4-stroke, air-cooled gasoline engine. With a displacement of 688 cc (cubic centimeters), which indicates the total volume of all the cylinders in the engine.

Capable of producing up to 20.8 horsepower (HP) at 3,600 revolutions per minute (RPM). Honda engines are known for their fuel efficiency, helping users save on operating costs over the long term. The GX630 is designed to maximize fuel economy while maintaining high performance levels.

The GX630 is built with high-quality materials and undergoes rigorous testing to ensure durability even in demanding conditions. This reliability minimizes downtime and increases productivity for users. Designed to operate quietly and smoothly, reducing noise and vibration levels for improved comfort during use. Engineered for easy maintenance, with accessible components and user-friendly designs. Routine maintenance tasks such as oil changes, air filter replacement, and spark plug inspection can be performed with minimal effort.


Make Honda
Model GX630RH-QZB3
Type Small Engine
Fuel Gas Unleaded 86 Octane or Higher
Engine Type 4 Stroke OHV Twin Cylinder
Bore/Stroke 78 X 72
Displacement 688cc
Compression Ratio 9.3:1
Max Power 20.8 HP @ 3600 RPM
Max Torque 35.6 ft. lbs. @ 2500 RPM
Ignition Type Digital CDI with Variable Timing
Dimensions (L x W x H) 16 x 16.25 x 17.25 in.
Starting Type Electric Start
Charging System 20 Amp
Oil Capacity 2.1 Qts
Dry Engine Weight 97 lbs.
Shaft Type Keyed - Straight
Shaft Diameter 1" Diameter, 1/4" Keyway
Shaft Length 2-7/8"
Shaft I.D. Thread Size 3/8"-24 Drilled and Tapped
Bolt Pattern 4 Bolt
Oil System Pressure lubrication, Oil Alert
Reduction Type None
Engine Cooling Type Forced Air Cooling
PTO shaft Rotation Counterclockwise (from PTO shaft side)
Governor System Centrifugal Mass Type
Air cleaner Dual Element
3-Year Limited Warranty
Remote Throttle and Choke
Two barrel inner-vent carburetor for more precise fuel metering
Cast Iron Sleeve
Smooth Performance
Easy to Use and Maintain
Simple throttle control
Easy, convenient, heavy duty control box
Easily accessible spark plug
Easy Starting
Hemispherical combustion chamber delivers rapid combustion
Automatic mechanical de-compression system
Emissions Compliant
Lower emissions, same power output!
CARB and EPA certified
No catalyst necessary
Precision camshaft design offers precise valve timing and optimal valve overlap for better fuel efficency
OHV design for increased efficiency and optimal power transfer
High compression ratio for better fuel efficiency
Precision engineered components result in lower vibration
Ball bearing supported crankshaft for greater stability
Exceptionally Quiet
Carburetor Butterfly
Pressure fed crankshaft bearings
Reduced mechanical noise due to light weight, noise-reducing materials
Forged steel crankshaft and rigid crankcase
Helical cut gears
Sophisticated air intake system
Proven Reliability
New carburetor chamber coating and carburetor filter help to protect against fuel impurities
Dual element air cleaner
Fuel Valve
Cross Reference Guide
Kohler: CH640
Briggs & Stratton: 386447
User Manual