The Honda GC135 is an 135 cc (8.2 cu-in) single-cylinder, air-cooled, four-stroke internal combustion gasoline engine with horizontal shaft, manufactured by Honda Motor Company since 1997 for general-purpose applications.
This engine has a single-cylinder, compact combustion chamber, tough resin overhead cam for durability and quietness and uniblock construction reduce fuel consumption. The Honda GC135 engine has transistorized magneto ignition, horizontal type carburetor, and recoil starter.
A 64.0 mm (2.5 in) cylinder bore and 42.0 mm (1.7 in) piston stroke give the engine a total of 135 cc of displacement. Compression ratio is 8.5:1. It produces 4.0 PS (2.9 KW; 4.0 HP) at 3,600 rpm and 8.6 Nm (0.9 kg·m; 6.35 lbf·ft) at 2,500 rpm of peak torque.
General information
| Engine Specifications | |
| Model | GC135 |
| Type | 4-stroke, OHC, single cylinder |
| Displacement | 135 cm 3 (8.2 cu-in) |
| Max. horsepower | 4.0 PS (2.9 KW; 4.0 HP) at 3,600 rpm |
| Max. torque (crank PTO) | 8.6 Nm (0.9 kg·m; 6.35 lbf·ft) at 2,500 rpm |
| Carburetor | Horizontal type, butterfly valve |
| Cooling system | Forced-air |
| Ignition system | Transistorized magneto ignition |
| Lubricating system | Splash |
| Starting system | Recoil starter |
| Stoping system | Ignition primary circuit ground |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Fuel tank capacity | 1.7 liters (1.8 US.qts, 1.5 Imp. qts) |
| Fuel consumption | 230 g/HPh |
| PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Dimensions and Weight
| S | Q | W | V | P | ||||
| Length, mm (in) | 321 (12.6) | 330 (13.0) | 347 (13.7) | 340 (13.4) | 330 (13.0) | |||
| Width, mm (in) | 369 (14.5) | |||||||
| Height, mm (in) | 315 (12.4) | |||||||
| Dry weight, kg (lb) | 11.2 (24.7) | |||||||
| Operating weight, kg (lb) |
13.0 (28.7) | |||||||
Cylinder Block and Head
| Cylinder block | ||
| Compression ratio: | 8.5:1 | |
| Bore x Stroke | 64.0 mm X 42.0 mm (2.5 x 1.7 in) | |
| Sleeve internal diameter | 64.00 mm (2.52 in) | |
| Piston skirt outer diameter | 63.969 mm (2.5185 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Piston ring side clearance (Top): | 0.015-0.045 mm (0.0006-0.0018 in) | |
| Piston ring side clearance (Second): | 0.015-0.045 mm (0.0006-0.0018 in) | |
| Piston ring side clearance (Oil): | 0.015-0.045 mm (0.0006-0.0018 in) | |
| Piston ring end gap (Top): | 0.200-0.350 mm (0.008-0.014 in) | |
| Piston ring end gap (Second): | 0.300-0.450 mm (0.012-0.018 in) | |
| Piston ring end gap (Oil): | 0.150-0.350 mm (0.006-0.014 in) | |
| Ring width (Top): | 1.5 mm (0.06 in) | |
| Ring width (Second): | 1.5 mm (0.06 in) | |
| Ring width (Oil): | 2.5 mm (0.10 in) | |
| Connecting rod small end ID | 13.005 mm (0.512 in) | |
| Connecting rod big end ID | 26.02 mm (1.024 in) | |
| Crankpin outer diameter | 25.98 mm (1.023 in) | |
| Main journal outer diameter |
PTO side: 27.993 mm (1.1021 in) Flywheel side 25.393 mm (0.9997 in) |
|
| Cylinder Head | ||
| Warpage (limit) | 0.10 mm (0.004 in) | |
| Valve Arrangement: | OHC | |
| Valves: | 2 | |
| Valve stem outer diameter (INTAKE): | 5.480 mm (0.216 in) | |
| Valve stem outer diameter (EXHAUST): | 5.440 mm (0.214 in) | |
| Valve guide inner diameter (INTAKE): | 5.5 mm (0.2165 in) | |
| Valve guide inner diameter (EXHAUST): | 5.5 mm (0.2165 in) | |
| Spring free length | 34.0 mm (1.34 in) | |
Tightening torque specs
| Tightening torque specs | |
| Air cleaner case bolt | 10 Nm; 1.0 kg·m; 7 ft·lb |
| Crankcase cover bolt | 12 Nm; 1.2 kg·m; 8.6 ft·lb |
| Connecting rod bolt | 12 Nm; 1.2 kg·m; 8.6 ft·lb |
| Valve adjusting lock nut | 8 Nm; 0.8 kg·m; 5.8 ft·lb |
| Cylinder head cover bolt | 12 Nm; 1.2 kg·m; 8.6 ft·lb |
| Oil drain plug bolt | 24 Nm; 2.4 kg·m; 17 ft·lb |
| Flywheel nut | 52 Nm; 5.3 kg·m; 38 ft·lb |
| Governor arm nut | 10 Nm; 1.0 kg·m; 7 ft·lb |
| Muffler bolt | 12 Nm; 1.2 kg·m; 8.6 ft·lb |
| Recoil starter nut | 8.5 Nm; 0.85 kg·m; 6.1 ft·lb |
| Fan cover stud bolt | 12 Nm; 1.2 kg·m; 8.6 ft·lb |
| Fuel tank bolt, nut | 10 Nm; 1.0 kg·m; 7 ft·lb |
| Spark plug | 20 Nm; 2.0 kg·m; 14 ft·lb |
| Others | |
| 5 mm bolts, nuts | 5.5 Nm; 0.55 kg·m; 4.0 ft·lb |
| 6 mm bolts, nuts | 10 Nm; 1.0 kg·m; 7 ft·lb |
| 8 mm bolts, nuts | 24 Nm; 2.4 kg·m; 17 ft·lb |
| 10 mm bolts, nuts | 37 Nm; 3.7 kg·m; 27 ft·lb |
| 12 mm bolts, nuts | 55 Nm; 5.5 kg·m; 39.5 ft·lb |
Service Information
| Engine | |
| Maximum speed | 3,850 ± 150 rpm |
| Idle speed | 1,400 ± 150 rpm |
| Cylinder compression | 5.0 kg/cm2 (71 psi) at 600 rpm |
| Valve clearance | |
| Intake valve | 0.15 ± 0.04 mm (0.006 ± 0.002 in) |
| Exhaust valve | 0.20 ± 0.04 mm (0.008 ± 0.002 in) |
| Oil system | |
| Oil type | Honda 4-stroke or an equivalent (SE or SF) |
| Recommended oil | SAE 10W-30 |
| Oil capacity | 0.58 liters (0.6 US.qts, 0.5 Imp. qts) |
| Ignition system | |
| Ignition timing | 20° B.T.D.C. |
| Spark plug | NGK: BPR6ES |
| Spark plug gap | 0.7-0.8 mm (0.028-0.031 in) |
| Spark plug torque | 20 Nm; 2.0 kg·m; 14 ft·lb |
| Primary ignition coil resistance | 1.0-1.2 Ω |
| Secondary ignition coil resistance | 10.6-12.8 kΩ |
| Ignition coil air gap | 0.2-0.6 mm (0.008-0.024 in) |
| Carburetor | |
| Main jet | #60 |
| Float height | 9.2 mm (0.36 in) |
| Pilot screw opening | 2 turns out |
i have an older gc135 to run a water pump i am having a hard time starting it.Is there an on off switch i am missing there is a push/pull next to the pull cord does that have to be in or out. anything else would be appreciated
I too have an old GC135, I am not a mechanic and fortunately it starts first pull each time on full choke. There is no on /off switch.
Firstly try a new spark plug, if that fails then clean the magnets in the flywheel, the valve after a while start to leak so they will have to be ground in again, as the cylinder head is part of the block the only way I found this to be done is to put grinding paste on the valve seat then put the valve in and then fix it in the chuck of a battery powered drill switch it on and gently pull up after a while you will get a new seating, this cured my engine
That is choke pull out to choke and when it starts let run for a few seconds then push lever back in.