163cc Engine Horsepower Specs (CC to HP)
A 163 cc four-stroke engine does not have one fixed horsepower rating. Many small engines in this size range are rated around 4.8 to 5.5 hp, but the exact figure depends on the model and whether its rating is net or gross. Check the engine’s label or manual before choosing a replacement or judging its power.
A cubic-centimeter figure describes engine displacement: the volume swept by the piston, not the power the engine must produce. That is why two engines with the same displacement can have different horsepower ratings. If you are replacing a mower engine or comparing equipment, use the model’s published rating and confirm that the engine fits and meets the equipment maker’s requirements.
I use displacement as a starting point, not a buying decision. Horsepower, shaft dimensions, mounting pattern, and governed speed all matter. The steps below explain how to read a 163 cc engine rating and apply it to equipment safely.
163 cc Engine Horsepower: Ratings and Model-Specific Specs
A 163 cc rating tells you engine size, not a precise horsepower figure. Many four-stroke engines near this displacement fall around 4.8 to 5.5 hp, but those figures are examples, not a conversion rule. The engine maker’s exact model rating and test method are the reliable reference.
Why cc does not convert directly to horsepower
Horsepower measures power output; cc measures the engine’s swept volume. There is no fixed formula that turns 163 cc into one horsepower value. Design, operating speed, air flow, fuel delivery, and rating method all affect the result.
A useful example is Honda’s GX160. Honda lists its displacement as 163 cc and its net power as 3.6 kW, or about 4.8 mechanical hp, at 3,600 rpm. That is a model-specific published rating, not proof that every 163 cc engine makes 4.8 hp.
For converting a stated power rating, 1 mechanical horsepower equals about 745.7 watts. So 4.8 hp is about 3.58 kW, while 5.5 hp is about 4.10 kW. The conversion changes the units; it does not calculate horsepower from displacement.
Net and gross horsepower are not the same
Net and gross are different ways of measuring engine output. A net rating reflects power under stated test conditions with specified engine equipment in place. A gross rating is measured under a different setup. The exact procedures and conditions depend on the rating standard.
Do not compare a gross figure from one engine directly with a net figure from another as if they were equal. Look for the rating type, test speed, and manufacturer’s stated conditions. If the label gives only “hp,” check the manual or the manufacturer’s specification sheet for clarification.
| Figure or term | What it tells you | How to use it |
|---|---|---|
| 163 cc | Engine displacement | A size reference, not a power rating |
| 4.8 hp | About 3.58 kW | Confirm whether the rating is net or gross |
| 5.5 hp | About 4.10 kW | Use only if published for the exact model |
| 3,600 rpm | Engine speed for a stated rating or operating limit | Verify the model’s specified speed |
| Torque | Turning force at a stated speed | Useful for understanding load response; compare under matching test conditions |
What to check before buying a replacement
Start with the equipment maker’s engine requirements, not a general cc-to-hp chart. Match the engine’s approved power, shaft or PTO configuration, mounting pattern, and governed speed. PTO means the part of the engine that transfers power to the equipment.
A replacement that has the right displacement may still have the wrong shaft length, diameter, keyway, mounting holes, or control connections. A mismatch can prevent safe installation or proper operation. Also check the equipment manual for any restrictions on engine type or rated output.
A 163 cc figure is not a chainsaw bar-length, chain-pitch, or fuel-mix specification. Most small 163 cc outdoor-power engines are four-stroke engines and use gasoline without premixed two-cycle oil. Confirm fuel grade and any ethanol limits in the specific engine manual.
Equipment Setup and Safety Preparation
Before fitting or using a 163 cc engine, confirm the equipment’s requirements and inspect the machine. The engine’s horsepower alone does not establish compatibility. Shaft and mounting details, speed limits, guards, controls, and the intended load all affect whether the setup is suitable.
Worked fitment examples
Mower replacement scenario: Suppose a mower’s manual specifies an engine configuration and shaft dimensions. A 163 cc engine with a similar horsepower rating is not automatically a match. Compare its mounting pattern, shaft measurements, control layout, and approved speed with the mower specifications before installation.
Small machine comparison: If one 163 cc engine is listed at 4.8 hp net and another at 5.5 hp, first check whether both use the same rating method and conditions. Then compare the equipment maker’s required output and mechanical fit. Choosing the larger number alone does not confirm a safe upgrade.
These examples show why a model number is more useful than displacement alone. Record the old engine’s identification details and the equipment model before sourcing a replacement.
Pre-start checks
Before starting, use task-appropriate eye and hearing protection, gloves, and footwear. Check guards, controls, fasteners, and the work area. Clear away objects that could be struck or pulled into the equipment, and look for fuel or oil leaks.
Check the four-stroke crankcase oil level using the procedure in the manual. Confirm that the fuel is fresh and correct for the engine, and that the attachment and guard are approved for the equipment. Start only as the manufacturer directs, with the starting area clear.
For tree work, follow applicable ANSI Z133 and OSHA requirements. A 163 cc engine rating does not make an engine suitable for a chainsaw or establish a safe chainsaw setup.
Field Operation, Maintenance, and Tuning
Use the engine within the equipment maker’s approved load and speed range. Keep guards installed, follow the manual’s operating steps, and do not change the governor to chase a higher horsepower figure. Stop if the engine surges, overheats, loses power, or develops abnormal vibration.
Match the load to the equipment
Horsepower is not the only factor that affects how an engine handles work. The equipment’s design and load matter too. A mower blade, pump, or other driven part places a different demand on an engine. Use the equipment for its intended task and avoid forcing it through heavy material or a binding attachment.
The governor helps control engine speed under changing loads. Do not bypass it or adjust it outside the manufacturer’s procedure. Raising speed can overspeed the engine and the driven blade or attachment, creating a risk of severe component failure. Stop operation if you suspect overspeed, binding, or abnormal vibration.
Service by the model specification
Oil grade, oil capacity, idle speed, maximum governed rpm, and torque are model- and application-specific. Find them in the engine manual or on the identification label; do not infer them from 163 cc. Use the stated maintenance schedule and specified parts.
For a four-stroke engine, keep crankcase oil separate from gasoline. Do not add two-cycle oil to the fuel unless the specific engine manual explicitly instructs it. Typical 163 cc outdoor-power engines are four-stroke, but the manual for the exact model is the final guide.
If power drops, check routine items described in the manual, such as the air filter, spark plug, fuel condition, and oil level. Avoid changing speed settings or altering the governor as a troubleshooting shortcut. If a fault persists, use an authorized service procedure or qualified repair help.
Shutdown, Storage, and Seasonal Care
After use, stop the equipment using its stated procedure and allow hot parts to cool before refueling or maintenance. Clean debris, inspect for damage, and note service needs. For storage, follow the engine maker’s fuel and preservation instructions rather than applying a general rule to every model.
Before putting equipment away, check for loose fasteners, damaged guards, leaks, and blocked cooling areas. Record the engine model and any maintenance completed. These simple notes help you compare the right specifications and catch recurring problems at the next start.
Seasonal fuel handling varies by engine and fuel system. Follow the manual’s instructions for storage duration, fuel treatment, or draining. Do not guess at storage steps based only on displacement. When preparing the machine for use again, recheck oil, fuel, controls, and guards before starting.
The main takeaway is straightforward: 163 cc can help identify an engine’s size, but only the exact model specification tells you its rated power and operating limits. Confirm the rating method, fit, speed, and equipment requirements before you buy or run it.
How much horsepower does a 163 cc engine have?
There is no exact horsepower value based on displacement alone. Many engines near 163 cc are rated around 4.8 to 5.5 hp, but check the exact model’s published rating.
What is 4.8 hp in kilowatts?
Four-point-eight mechanical horsepower is about 3.58 kW. This converts a stated rating; it does not derive power from engine displacement.
What is 5.5 hp in kilowatts?
Five-point-five mechanical horsepower is about 4.10 kW. Confirm that the rating belongs to the exact engine model and note whether it is net or gross.
Is every 163 cc engine rated at 4.8 hp?
No. The Honda GX160 is a model-specific example listed at 3.6 kW, or about 4.8 hp net, at 3,600 rpm. Other engines can have different ratings.
Can I compare net and gross horsepower directly?
No. They use different test ratings and conditions. Compare figures only when their rating method and stated test conditions match.
Does more horsepower mean an engine will fit my mower?
No. Check the mower maker’s requirements, mounting pattern, shaft dimensions, controls, and governed speed. Displacement or horsepower alone cannot confirm fit.
Does a 163 cc four-stroke engine use premixed two-cycle fuel?
Typically, no. Four-stroke engines use gasoline and separate crankcase oil. Follow the exact engine manual for fuel requirements and any ethanol limits.
Can I increase horsepower by adjusting the governor?
Do not adjust or bypass the governor beyond the manufacturer’s procedure. Overspeed can damage the engine or driven parts and may cause catastrophic failure.
Does 163 cc tell me a chainsaw’s bar length or chain pitch?
No. Displacement does not specify bar length, chain pitch, or fuel-oil ratio. Use the chainsaw model’s specifications for those details.
Where can I find the exact horsepower rating?
Check the engine identification label, owner’s manual, or manufacturer’s specification sheet. Look for the model number, rating type, output, and stated test speed.
(This article was written by one of our staff writers, Harrison Croft. Visit our Meet the Team page.)
