The Honda GXV630 is a 688 cc (41.97 cu-in) V-twin cylinder air-cooled four-stroke internal combustion small gasoline engine with vertical shaft manufactured by Honda Motor Company for general-purpose applications, such as riding mowers and lawn tractors, construction equipment and other professional heavy-duty applications.
The Honda GXV630 engine has an OHV (overhead valve) design with 90° V-twin cylinders; horizontal type, two-barrel inner-vent carburetor with butterfly valve; digital C.D.I.(Capacitor Discharge Ignition) ignition system with variable timing and electric starter.
The GXV630 motor uses a hemispherical combustion chamber design. It offers a higher 9.3:1 compression ratio, higher power output and greater displacement in a more compact design. The cylinder bore is 78.0 mm (3.07 in) and the piston stroke is 72.0 mm (2.83 in). The GXV630 engine produces 21.1 PS (15.5 kW; 20.8 HP) of maximum horsepower at 3,600 rpm; 16.3 PS (12.0 kW; 16.0 HP) of continuous rated power at 3,600 rpm., and 48.3 N·m (4.93 kg·m, 35.6 ft·lb) of torque at 2,500 rpm.
General information
Engine Specifications | |
Model | GXV630 / GXV630R |
Type | 4-stroke, OHV, 90° V-twin |
Displacement | 688 cm 3 (41.97 cu-in) |
Max. horsepower | 21.1 PS (15.5 kW; 20.8 HP) at 3,600 rpm |
Max. torque (crank PTO) | 48.3 N·m (4.93 kg·m, 35.6 ft·lb) at 2,500 rpm |
Carburetor | Horizontal type, two barrel, inner-vent, butterfly valve |
Cooling system | Forced-air |
Ignition system | Digital C.D.I. with variable timing |
Lubricating system | Forced feed |
Starting system | Electric starter |
Stoping system | Ignition primary circuit open |
Fuel used | Unleaded gasoline (octane number 86 or higher) |
Fuel consumption | 4.7 L (1.24 US gal, 1.03 Imp gal) / h |
PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Dimensions and Weight
GXV630 | |
Length, mm (in) | 449 (17.7) |
Width, mm (in) | 420 (16.5) |
Height, mm (in) | 475 (18.7) |
Dry weight, kg (lb) | 46.5 (102.5) |
Cylinder Block and Head
The Honda GXV630 engine uses integrated cylinder and head, cast iron sleeve, a hemispherical combustion chamber, aluminum push rods with steel tips, racing inspired forged steel connecting rods and forged steel crankshaft with pressure fed crankshaft bearings,
Cylinder block | ||
Compression ratio: | 9.3:1 | |
Bore x Stroke | 78 X 72 mm (3.07 x 2.83 in) | |
Sleeve internal diameter | 78.000-78.015 mm (3.0709-3.0715 in) | |
Piston skirt outer diameter | 77.985-77.995 mm (3.0703-3.0707 in) | |
Ring side clearance | Top/Second | 0.050-0.080 mm (0.0020-0.0031 in) |
Ring end gap | Top/Second | 0.20-0.35 mm (0.008-0.0138 in) |
Oil (side rail | 0.20-0.70 mm (0.008-0.028 in) | |
Ring width | Top/Second | 1.140-1.155 mm (0.0449-0.0455 in) |
Connecting rod small end ID | 18.006-18.018 mm (0.7089-0.7094 in) | |
Piston pin outer diameter | 17.994-18.000 mm (0.7084-0.7087 in) | |
Crankpin diameter | 44.973-44.983 mm (1.7706-1.7710 in) | |
Crankshaft journal diameter | 39.984-40.000 mm (1.5742-1.5748 in) | |
Cylinder Head | ||
Warpage (limit) | 0.10 mm (0.004 in) | |
Valve Arrangement: | OHV | |
Valves: | 4 (2 per cylinder) | |
Stem outer diameter (standard): | INTAKE | 5.475-5.490 mm (0.2156-0.2161 in) |
EXHAUST | 5.435-5.450 mm (0.2140-0.2146 in) | |
Valve spring free length: | 38.3 mm (1.51 in) | |
Valve lifter internal diameter: | 6.010-6.040 mm (0.2366-0.2378 in) | |
Valve lifter shaft outer diameter: | 5.970-6.000 mm (0.2350-0.2362 in) | |
Camshaft journal diameter: | 16.982-17.000 mm (0.6686-0.6693 in) | |
Cam height: | INTAKE | 29.506-29.706 mm (1.1617-1.1695 in) |
EXHAUST | 29.410-29.610 mm (1.1579-1.1657 in) |
Tightening torque specs
Tightening torque specs | |
Connecting rod bolt | 22 Nm; 2.2 kg·m; 16 ft·lb |
Cylinder nut | 37 Nm; 3.8 kg·m; 27 ft·lb |
Oil drain plug bolt | 45 Nm; 4.5 kg·m; 33 ft·lb |
Flywheel nut | 235 Nm; 24.0 kg·m; 173 ft·lb |
Oil filter cartridge | 12 Nm; 1.2 kg·m; 9 ft·lb |
Tappet adjusting nut | 7.5 Nm; 0.75 kg·m; 5.5 ft·lb |
Governor arm nut | 11 Nm; 1.1 kg·m; 8 ft·lb |
Fuel pump cover screw | 4 Nm; 0.4 kg·m; 3 ft·lb |
Oil pressure switch | 9 Nm; 0.9 kg·m; 6.6 ft·lb |
Service Information
Engine | |
Maximum speed | 3,400 ± 150 rpm |
Idle speed | 1,400 ± 150 rpm |
Cylinder compression | 5.0-7.0 kg/cm2 (73-102 psi) at 500 rpm |
Valve clearance | |
Intake valve clearance | 0.08±0.02 mm |
Exhaust valve clearance | 0.10±0.02 mm |
Oil system | |
Oil type | Honda 4-stroke or an equivalent (SE or later) |
Recommended oil | SAE 10W-30 |
Oil capacity |
Without oil filter: 1.7 Liters (1.80 US qt, 1.50 Imp qt) With oil filter: 1.9 Liters (2.01 US qt, 1.67 Imp qt) |
Oil change interval | Every 6 month or 100 Hrs. |
Carburetor | |
Main jet |
Cylinder №1: #105 Cylinder №2: #110 |
Float height | 15.5 mm (0.61 in) |
Pilot screw opening |
Cylinder №1: 2 turns out Cylinder №2: 2-1/8 turns out |
Ignition system | |
Ignition timing | 9°-23° B.T.D.C. |
Spark plug | NGK: ZFR5F |
Spark plug gap | 0.7-0.8 mm (0.028-0.031 in) |
Ignition coil air gap | 0.4 ± 0.2 (0.016 ± 0.008) |
We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.
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