| Model | GX160 | GX200 | GX390 |
| Engine Type | Air-cooled 4-stroke OHV | Air-cooled 4-stroke OHV | Air-cooled 4-stroke OHV |
| Bore x Stroke | 68 X 45 mm | 68 X 54 mm | 88 X 64 mm |
| Displacement | 163 cm3 | 196 cm3 | 389 cm3 |
| Net Power Output* | 4.8 HP (3.6 kW) @ 3,600 rpm | 5.5 HP (4.1 kW) @ 3,600 rpm | 11.7 HP (8.7 kW) @ 3,600 rpm |
| Net Torque | 7.6 lb-ft (10.3 Nm) @ 2,500 rpm | 9.1 lb-ft (12.4 Nm) @ 2,500 rpm | 19.5 lb-ft (26.4 Nm) @ 2,500 rpm |
| PTO Shaft Rotation | Counterclockwise (from PTO shaft side) | Counterclockwise (from PTO shaft side) | Counterclockwise (from PTO shaft side) |
| Compression Ratio | 9.0 : 1 | 8.5:1 | 8.2:1 |
| Lamp/Charge coil options | 25W, 50W / 1A, 3A, 7A | 25W, 50W / 1A, 3A, 7A | 25W, 50W / 1A, 3A, 10A, 18A |
| Carburetor | Butterfly | Butterfly | Butterfly Float Type |
| Ignition System | Transistorized magneto | Transistorized magneto | Digital CDI with variable timing |
| Starting System | Recoil Starter | Recoil Starter | Recoil/electric |
| Lubrication System | Splash | Splash | Splash |
| Governor System | Centrifugal Mechanical | Mechanical | Centrifugal Mass Type |
| Air cleaner | Dual Element | Dual element | Dual element |
| Oil Capacity | 0.61 US qt. (0.58 L) | 0.63 US qt (0.6l) | 1.16 US qt (1.1 L) |
| Fuel Tank Capacity | 3.3 U.S. qts (3.1 liters) | 3.3 U.S. qts (3.1 liters) | 6.4 U.S. qts (6.1 liters) |
| Fuel | Unleaded 86 octane or higher | Unleaded 86 octane or higher | Unleaded 86 octane or higher |
| Dry Weight | 33 lbs. (15.1 kg) | 35 lbs. (16.1 kg) | 69 lb (31.5 kg) |
