The Honda GX240 K1/T1/UT1 is a 242 cc (14.8 cu-in) single-cylinder, air-cooled, four-stroke internal combustion small gasoline engine manufactured by Honda Motor Company for general-purpose applications.
This engine has an OHV design for increased efficiency and optimal power transfer; sophisticated air intake system; large capacity, multi-chamber exhaust system; heavy-duty recoil starter.
The Honda GX240 K1 produces 8.11 PS (8.0 HP, 6.0 kW) at 3,600 rpm and 17,0 Nm (1.7 kg·m, 12 lbf·ft) at 2,500 rpm of peak torque.
The GX240 K1/T1/UT1 is an old version, nowadays Honda Motor Co. produces a new GX240 R2/RT2/T2/U2/UT2 engine with CDI ignition system.
PTO Shaft Options
- E type – tapered shaft;
- H type – 1/6 reduction type PTO;
- L type – 1/2 reduction type PTO;
- P type – threaded type (SAE);
- Q type – straight shaft;
- R type – 1/2 reduction type PTO with centrifugal clutch;
- V type – tapered shaft;
General information
| Engine Specifications | |
| Model | GX240K1 |
| Type | 4-stroke, OHV, single cylinder, inclined by 25° |
| Displacement | 242 cm 3 (14.8 cu-in) |
| Max. horsepower | 8.11 PS (8.0 HP, 6.0 kW) at 3,600 rpm |
| Max. torque (crank PTO) | 17.0 Nm (1.7 kg·m, 12.0 lbf·ft) at 2,500 rpm |
| Carburetor | Horizontal type, butterfly valve |
| Cooling system | Forced-air |
| Ignition system | Transistorized magneto ignition |
| Lubricating system | Splash type |
| Starting system | Recoil or electric starter |
| Stoping system | Ignition primary circuit ground |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Fuel tank capacity | 6.0 liters (6.3 US.qts, 5.3 Imp. qts) |
| Fuel consumption | 313 g/kWh (230 g/HPh, 0.51 lb/HPh) |
| PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Dimensions and Weight
| S | Q | L | R | H | W | P | V | |
| Length, mm (in) | 355 (14.0) | 380 (15.0) | 405 (15.9) | 440 (17.3) | 425 (16.7) | 370 (14.6) | 380 (15.0) | 400 (15.7) |
| Width, mm (in) | 430 (16.9) | |||||||
| Height, mm (in) | 410 (16.1) | |||||||
| Dry weight, kg (lb) | 25 (55.1) | 25 (55.1) | 26.5 (58.4) | 30 (66.1) | 26.5 (58.4) | 25 (55.1) | 25 (55.1) | 25 (55.1) |
| Operating weight, kg (lb) |
30 (66.1) | 30 (66.1) | 31.5 (69.4) | 35 (77.2) | 31.5 (69.4) | 30 (66.1) | 30 (66.1) | 30 (66.1) |
Cylinder Block and Head
The Honda GX240 engine has a cast iron cylinder sleeve, ball bearing supported crankshaft, improved piston design, heavy duty balancer shaft. The piston has two compression rings and one oil ring. Precision camshaft design offers precise valve timing and optimal valve overlap for better fuel efficiency.
| Cylinder block | ||
| Compression ratio: | 8.2 | |
| Bore x Stroke | 73.0 X 58.0 mm (2.9 x 2.3 in) | |
| Sleeve internal diameter | 73.000 mm (2.8740 in) | |
| Piston skirt outer diameter | 72.985 mm (2.8734 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): | 0.200-0.400 mm (0.010-0.020 in) | |
| Piston ring end gap (Second): | 0.200-0.400 mm (0.010-0.020 in) | |
| Piston ring end gap (Oil): | 0.200-0.400 m (0.010-0.020 in) | |
| Ring width (Top): | 2.0 mm (0.080 in) | |
| Ring width (Second): | 2.0 mm (0.080 in) | |
| Ring width (Oil): | 2.8 mm (0.110 in) | |
| Piston pin outer diameter | 18.000 mm (0.7086 in) | |
| Pin bore inner diameter | 18.002 mm (0.7087 in) | |
| Conrod small end inner diameter | 18.005 mm (0.7089 in) | |
| Crankshaft outer diameter | 32.985 mm (1.2986 in) | |
| Cylinder Head | ||
| Warpage (limit) | 0.10 mm (0.004 in) | |
| Valve Arrangement: | OHV | |
| Valves: | 2 | |
| Valve stem diameter (INTAKE): | 6.59 mm (0.259 in) | |
| Valve stem diameter (EXHAUST): | 6.55 mm (0.258 in) | |
| Valve guide inner diameter (INTAKE): | 6.60 mm (0.260 in) | |
| Valve guide inner diameter (EXHAUST): | 6.60 mm (0.260 in) | |
| Stem clearance (INTAKE): | 0.010-0.037 mm (0.0004-0.0015 in) | |
| Stem clearancer (EXHAUST): | 0.050-0.077 mm (0.0020-0.0030 in) | |
| Camshaft cam height (INTAKE): | 31.520-31.920 mm (1.241-1.257 in) | |
| Camshaft cam height (EXHAUST): | 31.560-31.960 mm (1.243-1.258 in) | |
| Seat width: | 1.100 mm (0.0430 in) | |
| Spring free legth: | 39.0 mm (1.540 in) | |
| Camshaft outer diameter: | 15.984 mm (0.6293 in) | |
MAINTENANCE DATA
| Engine | |
| Maximum speed | 3,850 ± 150 rpm |
| Idle speed | 1,400 ± 150 rpm |
| Cylinder compression | 6.0-8.5 kg/cm2 (85-151 psi) at 600 rpm |
| Valve clearance | |
| Intake valve | 0.15 ± 0.02 mm (0.006 ± 0.001 in ) |
| Exhaust valve | 0.20 ± 0.02 mm (0.008 ± 0.001 in) |
| Carburetor | |
| Main jet | Externally vented carburetor bowl: #85 Internally vented carburetor bowl: #92 |
| Float height | 13.2 mm (0.52 in) |
| Pilot screw opening | 2 |
| Oil system | |
| Oil type | Honda 4-stroke or an equivalent (SG.SF/CC.CD) |
| Recommended oil | SAE 10W-30 |
| Oil capacity | 1.1 liters (1.16 US.qts, 0.97 Imp. qts) |
| Ignition system | |
| Ignition timing | 20 ° B.T.D.C (Fixed) |
| Spark plug | NGK: BP6ES, BPR6ES NIPPONDENSO: W20EP-U, W20EPR-U |
| Spark plug gap | 0.7-0.8 mm (0.028-0.031 in) |
| Spark plug cap | 7.5-12.5 kΩ |
| Primary ignition coil resistance | 0.8-1.0 Ω |
| Secondary ignition coil resistance | 5.9-7.1 kΩ |
| Ignition coil air gap | 0.4 ± 0.2 (0.016 ± 0.008) |
Tightening torque specs
| Tightening torque specs | |
| Connecting rod bolt (M8x1.25 Special) | 14 Nm; 1.4 kg·m; 10 ft·lb |
| Cylinder head bolt (M10x1.25) | 35 Nm; 3.5 kg·m; 25 ft·lb |
| Flywheel nut (M16x1.5 Special) | 115 Nm; 11.5 kg·m; 83 ft·lb |
| Rocker arm pivot lock nut (M6x0.5) | 10 Nm; 1.0 kg·m; 7 ft·lb |
| Rocker arm pivot bolt (M8x1.25 Special) | 24 Nm; 2.4 kg·m; 17 ft·lb |
| Crankcase cover bolt (M8x1.25) | 24 Nm; 2.4 kg·m; 17 ft·lb |
| Oil level switch joint nut (M10x1.25) | 10 Nm; 1.0 kg·m; 7 ft·lb |
| Fuel filter joint nut (M10x1.25) | 2 Nm; 0.2 kg·m; 1.4 ft·lb |
| Muffler mounting nut (M8x1.25) | 24 Nm; 2.4 kg·m; 17 ft·lb |
| Air cleaner wing nut (M6x1.0) | 9 Nm; 0.9 kg·m; 6.5 ft·lb |
| Oil drain bolt (M12x1.5) | 23 Nm; 2.3 kg·m; 17 ft·lb |
| Fuel tank bolt (M8x1.25) | 24 Nm; 2.4 kg·m; 17 ft·lb |
| Air cleaner mounting nut (M6x1.0) | 10 Nm; 1.0 kg·m; 7 ft·lb |
| Fuel strainer cup (M24x1.0) | 4 Nm; 0.4 kg·m; 2.9 ft·lb |
| Standard torque values | |
| Bolt, nut (5 mm) | 5.5 Nm; 0.55 kg·m; 4.0 ft·lb |
| Bolt, nut (6 mm) | 10 Nm; 1.0 kg·m; 7 ft·lb |
| Bolt, nut (8 mm) | 24 Nm; 2.4 kg·m; 17 ft·lb |
| Bolt, nut (10 mm) | 37.5 Nm; 3.75 kg·m; 27 ft·lb |
| Bolt, nut (12 mm) | 55 Nm; 5.5 kg·m; 40 ft·lb |
Engine applications
- Pressure washers
- Commercial lawn and garden equipment
- Tillers / cultivators
- Generators
- Construction / industrial equipment
- Agricultural equipment
- Small vehicles
- Water pumps
great site – valuable information but… on this particular engine https://www.engine-specs.net/honda/gx240.html there is a typo error in the oil specs.. your site list 1. 1 L (correct) but lists as 1.16 GAL
Thanks, fixed
Honda discontinued the carburetor 16100-ZE2-A51. Is there a non-Honda replacement (used on FR800)?
Hi Jim, long time since your post, not sure if you have an answer or still interested, my predicament as well. last year bought a Chinese knock off, cheap brand says Farmer Tec, box says “fits Honda GX 240”, which it does but not exactly the specs of the original Keihin. My engine, on a generator, 30 years old but little work, 242 cc I believe the modern GX 240 has the same 270 cc capacity so the replacement carby has a larger venturi diameter and a larger main jet, the result is the revs hunt up and down. I have tried replacing the main jet with the one from the Keihin, still no good next I will try to close down the venturi, 17.4 to 15.9mm and hope that works, had thought about trying to see if the likes of Kawasaki, Yamaha have one like it?