The Honda iGX390 is a 0.39 l (389 cc, 23.7 cu·in) single-cylinder air-coolled 4-stroke internal combustion small gasoline (petrol) engine with horizontal shaft, manufactured by Honda Motor for general-purpose applications. The iGX390 is a modified version of the GX390 engine with STR (Self Tuning Regulator) governor, so it is suitable for applications that require features like Auto-Idle and Auto-Choke.
The iGX390 engine has variable ignition timing C.D.I.(Capacitor Discharge Ignition) type magneto ignition, horizontal type, butterfly valve carburetor, and recoil or electric starter motor. The iGX390 cylinder bore is 88.0 mm (3.5 in) and piston stroke is 64.0 mm (2.5 in), compression ratio rating is 8.2:1.
The Honda iGX390 produces 11.7 HP (8.7 kW; 11.8 PS) at 3600 rpm of net power or 9.4 HP (7.0 kW) at 3600 rpm of continuous rated power and 26.5 N·m (2.7 kgf·m, 19.5 lb·ft) at 2500 rpm of net torque.
General information
| Engine Specifications | |
| Model | iGX390 |
| Type | 4-stroke, OVH, single cylinder, inclined by 25° |
| Displacement | 289 cm 3 (23.7 cu·in) |
| Max. horsepower | 11.7 HP (8.7 kW; 11.8 PS) at 3600 rpm |
| Max. torque | 26.5 N·m (2.7 kgf·m, 19.5 lb·ft) at 2500 rpm |
| Carburetor | Horizontal type, butterfly valve |
| Cooling system | Forced-air |
| Ignition system | Digital C.D.I.(Capacitor Discharge Ignition) with variable ignition timing |
| Lubricating system | Forced splash |
| Starting system | Recoil and Starter motor |
| Stoping system | Ignition exciter coil circuit open |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Fuel consumption | 3.5 Liters (0.92 US gal, 0.77 Imp gal) / h |
| PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Cylinder Block and Head
The Honda iGX390 has 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. The engine has integrated ECU (electronic control unit) with a self-tuning regulator (STR) governor system.
| Cylinder block | ||
| Compression ratio: | 8.2:1 | |
| Bore x Stroke | 88 X 64 mm (3.5 x 2.5 in) | |
| Sleeve internal diameter | 88.000-88.017 mm (3.4646-3.4652 in) | |
| Piston skirt outer diameter | 87.975-87.985 mm (3.4635-3.4640 mm) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Ring side clearance | Top | 0.015-0.060 (0.0006-0.0024) | Second | 0.030-0.060 (0.0012-0.0024) |
| Ring end gap | Top | 0.20-0.35 mm (0.0079-0.0138 in) | Second | 0.35-0.50 mm (0.0138-0.0197 in) |
| Oil (side rail) | 0.2-0.7 mm (0.01-0.03 in) | |
| Ring width | Top | 1.160-1.190 mm (0.0457-0.0470 in) |
| Second | 1.160-1.175 mm (0.045-0.0463 in) | |
| Piston pin outer diameter | 19.994-20.000 mm (0.7872-0.7874 in) | |
| Connecting rod small end inner diameter | 20.005-20.020 mm (0.7876-0.7882 in) | |
| Connecting rod big end inner diameter | 36.025-36.039 mm (1.4183-1.4189 in) | |
| Crankpin outer diameter | 35.975-35.985 mm (1.4163-1.4167 in) | |
| Cylinder Head | ||
| Warpage (limit) | 0.10 mm (0.004 in) | |
| Valve Arrangement: | OHV | |
| Valves: | 2 | |
| Stem outer diameter (standard): | INTAKE | 6.575-6.590 mm (0.2589-0.2594 in) |
| EXHAUST | 6.535-6.550 mm (0.2573-0.2579 in) | |
| Cam height: | INTAKE | 32.498-32.698 mm (1.2794-1.2873 in) |
| EXHAUST | 31.985-32.185 mm (1.2592-1.2671 in) | |
| Camshaft outer diameter: | 15.966-15.984 mm (0.6286-0.6293 in) | |
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 |
Maintenance data
| Engine | |
| Maximum speed | 3,600 ± 150 rpm |
| Idle speed | 1,400 ± 150 rpm |
| Cylinder compression | 13.2 kg/cm2 (187 psi, 1.29 MPa) at 600 rpm |
| Valve clearance | |
| Intake valve | 0.15 ± 0.02 (0.006 ± 0.001) |
| Exhaust valve | 0.20 ± 0.02 (0.008 ± 0.001) |
| Carburetor | |
| Main jet | BE92B A: #100 |
| Float height | 13.2 mm (0.52 in) |
| Pilot screw opening | BE92B A: 3 turns out |
| Oil system | |
| Oil type | Honda 4-stroke or an equivalent (SE or later) |
| Recommended oil | SAE 10W-30 |
| Oil capacity | 1.1 L (1.16 US gal, 0.97 lmp qt) |
| Ignition system | |
| Ignition timing | B.T.D.C. 10° / 1,400 rpm |
| Spark plug | NGK: BPR6ES DENSO: W20EPR-U |
| Spark plug gap | 0.7-0.8 mm (0.028-0.031 in) |
| Ignition coil air gap | 0.2-0.6 mm (0.01 – 0.02 in) |
| Starter motor | |
| Brush length | 7.0 mm (0.28 in) limit: 3.5 mm (0.14 in) |
| Mica depth | 1.0 mm (0.04 in) limit: 0.2 (0.01) |
Author:
There is a red light on it what does this mean? It keeps flashing
low oil alert
can i buy A dr pro XL 321 with the honda igx390 11.7 8.7kw engine with electronic control unit and self turning regulator governor system.
Greetings,
what is the recommended hours use between oil change?
Thank you.
What is the spark advance at 3000 rpm?