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Honda GX-610 Engine

General Technical Data

Honda GX610 Engine Specifications

Engine Model ................ Honda GX610
Engine Type ................ 4-cycle overhead valve V-twin gasoline engine
Number of Cylinders ................ 2
Displacement, cu.in (cc) ................ 37.5 (614)
Engine Bore, in (mm) ................ 3.03 (77.0)
Engine Stroke, in (mm) ................ 2.61 (66.0)
Rated Engine Power, hp (kW) ................ 18.0 (13.4)
Rated Engine Speed, rpm ................ 3600
Maximum Torque, Nm (ft-lbs) ................ 43.2 (31.8)
Torque Speed, rpm ................ 2500
Compression Ratio ................ 8.3:1
Valve Arrangement ................ OHV
PTO Shaft Rotation ................ Counterclockwise (from PTO side)
Lubrication System ................ Forced
Air Cleaner ................ Dual element
Cooling System ................ Forced air
Ignition System ................ Transistorized magneto
Stopping System ................ Primary circuit ground
Starting System ................ Recoil or electric starter

Fuel System

Fuel System Type ................ Carburetor
Carburetor Type ................ Horizontal, butterfly valve
Governor Type ................ Centrifugal
Fuel Consumption, lb/Hph (g/kWh) ................ 0.51 (313)
Fuel Type ................ Gasoline (86 or higher)

Dimensions and Weight

Length, in (mm) ................ 15.3 (388)
Width, in (mm) ................ 18.0 (457)
Height, in (mm) ................ 17.8 (452)
Net Weight, lbs (kg) ................ 92.6 (42.0)
Operating Weight, lbs (kg) ................ 94.8 (43.1)

Honda GX610 Maintenance Data

Cylinder Block and Valves

Cylinder Bore Inside Diameter (Maximum), in (mm) ................ 3.038 (77.170)
Cylinder Compression, psi (kPa) ................ 85-114 (600-800)
Cylinder Head (Max. Out of Flatness), in (mm) ................ 0.004 (0.10)
Intake Valve Clearance, in (mm) ................ 0.006 (0.15)
Exhaust Valve Clearance, in (mm) ................ 0.008 (0.20)

Engine Oil and Filters

Engine Oil Type (Summer) ................ SAE 10W-30
Engine Oil Type (Winter) ................ SAE 5W-30
API Service Classifications ................ SG or SF
Oil Capacity (with Filter), qts (L) ................ 1.9 (1.8)
Oil Filter Part Number ................ 15400-ZJ1-004
Air Filter Part Number ................ 17210-ZJ1-842
Fuel Filter Part Number ................ 16910-ZE8-015

Carburetor Adjustment

Main Jet ................ #92
Idle Fuel ................ 1-7/8 turns out
Float Height, in (mm) ................ 0.55 (14.0)
Low Idle Speed, rpm ................ 1400±150
High Idle Speed, rpm ................ 3200±150

Ignition System

Spark Plug Type ................ NGK ZGR5A or Denso J16CR-U
Spark Plug Gap, in (mm) ................ 0.028-0.032 (0.70-0.80)
Module Air Gap, in (mm) ................ 0.008-0.024 (0.20-0.60)
Ignition Timing, deg ................ 20 BTDC
Spark Plug Torque, Nm (ft-lbs) ................ 18 (13)

Service Intervals

Service Air Filter Element ................ Every 50 hours
Change Engine Oil ................ Every 100 hours
Check and Adjust Spark Plug ................ Every 100 hours
Replace Engine Oil Filter ................ Every 300 hours
Replace Air Filter Element ................ Every 300 hours
Replace Fuel Filter Element ................ Every 300 hours
Check Carburetor Adjustment ................ Every 300 hours
Check and Adjust Valve Clearance ................ Every 300 hours
Replace Spark Plug ................ Every 300 hours

Honda GX610 Service Specifications

Cylinder Block

Cylinder Bore Inside Diameter (Std), in (mm) ................ 3.0314-3.0320 (77.000-77.015)
Cylinder Bore Inside Diameter (Wear Limit), in (mm) ................ 3.038 (77.170)
Connecting Rod Small End Inside Diameter (Std), in (mm) ................ 0.7089 (18.005)
Connecting Rod Small End Inside Diameter (Wear Limit), in (mm) ................ 0.711 (18.07)
Connecting Rod Big End Oil Clearance, in (mm) ................ 0.0012-0.0022 (0.030-0.056)
Crankshaft Journal Outside Diameter (Main), in (mm) ................ 1.4961 (38.000)
Crankshaft Journal Outside Diameter (Pin), in (mm) ................ 1.5746 (39.995)

Cylinder Head and Valves

Cylinder Head (Max. Out of Flatness), in (mm) ................ 0.004 (0.10)
Intake Valve Clearance, in (mm) ................ 0.006±0.001 (0.15±0.02)
Exhaust Valve Clearance, in (mm) ................ 0.008±0.001 (0.20±0.02)
Intake Valve Stem Outside Diameter (Std), in (mm) ................ 0.2594 (6.59)
Intake Valve Stem Outside Diameter (Wear Limit), in (mm) ................ 0.254 (6.44)
Exhaust Valve Stem Outside Diameter (Std), in (mm) ................ 0.2579 (6.55)
Exhaust Valve Stem Outside Diameter (Wear Limit), in (mm) ................ 0.252 (6.40)
Valve Guide Inside Diameter (Intake/Exhaust), in (mm) ................ 0.2598 (6.60)
Intake Valve Guide To Stem Clearance, in (mm) ................ 0.0004-0.0016 (0.010-0.040)
Exhaust Valve Guide To Stem Clearance, in (mm) ................ 0.0020-0.0031 (0.050-0.080)
Valve Seat Width (Intake/Exhaust), in (mm) ................ 0.04 (1.10)
Valve Spring Free Length, in (mm) ................ 1.54 (39.00)
Valve Lifter Shaft Outside Diameter, in (mm) ................ 0.2362 (6.00)
Valve Lifter Inside Diameter, in (mm) ................ 0.2366 (6.01)
Cam Height (Std), in (mm) ................ 1.1758 (29.865)
Cam Height (Wear Limit), in (mm) ................ 1.16 (29.50)
Camshaft Journal Outside Diameter, in (mm) ................ 0.6687 (16.985)

Piston and Piston Rings

Piston Pin Bore Inside Diameter (Std), in (mm) ................ 0.7087-0.7090 (18.002-18.008)
Piston Pin Bore Inside Diameter (Wear Limit), in (mm) ................ 0.7103 (18.042)
Piston Skirt Outside Diameter, in (mm) ................ 3.0309 (76.985)
Piston to Cylinder Bore Clearance, in (mm) ................ 0.0006-0.0020 (0.015-0.052)
Piston Pin Outside Diameter (Std), in (mm) ................ 0.7084-0.7087 (17.994-18.000)
Piston Pin Outside Diameter (Wear Limit), in (mm) ................ 0.7068 (17.954)
Top Compression Ring Width, in (mm) ................ 0.0783 (1.99)
Second Compression Ring Width, in (mm) ................ 0.0783 (1.99)
Top Compression Ring to Groove Side Clearance, in (mm) ................ 0.0012-0.0024 (0.030-0.060)
Second Compression Ring to Groove Side Clearance, in (mm) ................ 0.0012-0.0024 (0.030-0.060)
Top Compression Ring End Gap, in (mm) ................ 0.008-0.016 (0.20-0.40)
Second Compression Ring End Gap, in (mm) ................ 0.008-0.016 (0.20-0.40)
Ring End Gap (Wear Limit), in (mm) ................ 0.04 (1.00)

Honda GX610 Tightening Torque Specs

Cylinder Head Bolt (M10x1.25) ................ 34 Nm (25 ft-lb)
Cylinder Head Cover Bolt (M6x1.0) ................ 9 Nm (6.5 ft-lb)
Cylinder Head Stud Bolt (M8x1.25) ................ 18 Nm (13 ft-lb)
Connecting Rod Bolt (M6x1.0) ................ 12 Nm (9 ft-lb)
Flywheel Nut (M20x1.5) ................ 196 Nm (145 ft-lb)
Oil Drain Bolt (M14x1.5) ................ 39 Nm (29 ft-lb)
Oil Pump Cover Bolt (M6x1.0) ................ 10 Nm (7 ft-lb)
Fuel Pump Screw (M5x0.8) ................ 4 Nm (2.9 ft-lb)
Oil Filter Holder (M20x1.5) ................ 18 Nm (13 ft-lb)
Governor Arm Nut (M6x1.0) ................ 11 Nm (8 ft-lb)
Carburetor Bolt (M6x1.0) ................ 9 Nm (6.5 ft-lb)
Spark Plug (M14x1.25) ................ 18 Nm (13 ft-lb)