| Spec | GX120 | GX160 |
|---|---|---|
| Displacement | 122 cc | 163 cc |
| Bore × stroke | 60 × 43.5 mm | 68 × 45 mm |
| Net power | 3.2 hp (2.4 kW) @ 3,600 rpm | 4.8 hp (3.6 kW) @ 3,600 rpm |
| Net torque | 5.5 lb-ft (7.3 Nm) @ 2,500 rpm | 7.6 lb-ft (10.3 Nm) @ 2,500 rpm |
| Compression ratio | 8.3:1 | 9.0:1 |
| Oil capacity | 0.59 US qt (0.56 L) | 0.61 US qt (0.58 L) |
| Fuel tank | 2.1 US qt (2 L) | 3.3 US qt (3.1 L) |
| Dry weight | 28.9 lb (13.2 kg) | 33 lb (15.1 kg) |
| Ignition | Transistorized magneto | Transistorized magneto |
| Starting | Recoil | Recoil |
| Size (L × W × H, min) | 11.7 × 13.6 × 13.0 in (297 × 346 × 329 mm) | 12.2 × 14.3 × 13.6 in (312 × 362 × 346 mm) |
Source: Honda Engines official specification pages (engines.honda.com/models/model-detail/mid-gx), checked 2 Nov 2026. Power is SAE J1349 net output measured by Honda; engines installed in equipment may vary. This site is independent and not affiliated with Honda.
What the difference means
- Torque is what you feel in a tiller, pump or go-kart pulling from low speed: 5.5 vs 7.6 lb-ft at 2,500 rpm.
- Mounting: both share Honda’s same engine family, so overall size is close (11.7 × 13.6 × 13.0 in (297 × 346 × 329 mm) vs 12.2 × 14.3 × 13.6 in (312 × 362 × 346 mm)). Still check the bolt pattern and shaft for your exact type before swapping.
- Shaft: both come in several PTO shaft types (straight, tapered, threaded, reduction). The type letter after the model name on the engine label tells you which.
- Fuel use rises with load and displacement; the bigger engine only costs more fuel when you actually use its extra power.
Rule of thumb: pick the smaller engine when the equipment maker lists it as an option and you run it at part load; pick the larger one for pumps, splitters and karts that run near full load for long periods.