How Much Horsepower Does A Lawnmower Have?

Horsepower is the amount of work a machine can hold. The machine’s ability to do work increases if the horsepower is high. So, choosing a lawnmower with great horsepower is important to accomplish the goal.

On average, the horsepower of a lawnmower’s engine ranges from 3-40 HP. Riding lawnmowers produces around 10-40 HP, and push-mowers produce around 2-7 HP. Most small lawnmowers are rated in torque, whereas larger mowers, like riding mower, is rated in HP, so you cannot compare them directly.

This article will help you to know how much horsepower a lawnmower has and the factors that affect horsepower in a lawnmower.

What is the actual meaning of horsepower? How to measure it?

Generally, horsepower means the total amount of work the machine can hold. 

1 HP machine can move a 1-foot distance in 1 minute with 15000 kg of work.

So, you should choose a lawnmower with high horsepower as it will be able to run more, and you will get faster results. 

You can easily measure the horsepower of a machine by observing its weight, time, and distance. 

If a riding mower weighs 33000 kg and takes 1 minute to move 1 foot, it means the total power the lawnmower produces is 2 HP.

But if the riding lawnmower fails to move, the machine’s horsepower is 0.

That’s how you can easily measure horsepower.

How much horsepower do different lawnmowers have?

Horsepower differs from the lawnmower type. 

So, let’s discuss the horsepower of different lawnmowers. 

Push lawnmower

For a push mower, the normal engine size of the gas-powered machine comes with 160 cc, and battery-powered comes with 40-60 volts. 

So, the average horsepower of a push lawnmower is 4.5-5.0.

Normal mowers, which are cheap, come with a horsepower ranging from 3.0 to 4.0. 

But lawnmowers with low horsepower have a low ability to do work.  

A low-powered push lawnmower is only recommended for those who don’t like physical work and have a smaller lawn. 

But if the owner has a big lawn, mowing with the low-powered push mower will require a lot of time and great physical strength. 

But there are also self-propelled push lawnmowers that save time and energy. 

The ability to do work is much more than the normal push mowers. 

Self-propelled push mowers produce 5.0 to 7.0 HP. 

These push mowers can complete work in less time and don’t need much physical strength. 

If your lawn is ½ acre, then this mower is highly recommended. 

Electric lawnmower

An electric lawnmower is usually built for mowing smaller lawns and plain surfaces. 

This is the most environmentally friendly mowing equipment. So, you can’t compare it with gas-powered lawnmowers.

An electric lawnmower with 12 amps is the most common power source for smaller yards. 

If the power is less than that, you might face difficulty mowing your lawn. 

Also, if you have a larger yard, don’t consider this an option because it is only best for flat and smaller lawns. 

Riding lawnmowers

If you have a more than ½ acre lawn, it becomes quite difficult to mow with the regular and self-propelled push lawnmower. 

So, riding lawnmowers are recommended for mowing a huge lawn. 

Riding lawnmower engine produces horsepower ranging from 12.5 to 25, depending on the brand and model. 

But the most common range is 20 HP in the riding lawnmower. 

There are also riding lawnmowers with low horsepower, just like normal or self-propelled push mowers, but they are only suitable for small lawns. 

But if the lawn is 1 acre or more than that, with lots of slopes, then riding lawnmowers with great horsepower will be best to use. 

Also read: How Fast Can A Riding Lawn Mower Go? (+7 Tips To Ride Faster)

Surfer lawnmowers

This is a new variety of lawnmowers where you can stand and mow the lawn just like surfing. 

This machine is a mixture of both push and riding lawnmowers.

The working capability of this machine is extremely high compared to push and riding lawnmowers. 

Surfer lawnmowers come with 15-23 HP or even more, depending on the size. 

This lawnmower is the latest edition and has a lower cost than riding lawnmowers. 

If you want a lawnmower with high horsepower and an affordable price, then this lawnmower is one of the best choices.

How to know horsepower by engine sizes?

Earlier, most small-engine lawnmowers were categorized by horsepower to notify the individual about the machine’s power capacity. 

But now, you will see that small-engine lawnmowers are no longer rated with horsepower. 

Instead, it is now measured as cubic centimeters (cc). 

You can get confused by noticing the power capacity in cc ratings. 

So, let’s help you out in this situation.

125cc-150cc

If your lawnmower shows 125-140cc ratings, the power ranges between 3 to 4HP. This engine is mostly used for smaller yards. 

Lawnmowers with 150cc have a bit higher horsepower, i.e., 5 HP. But a 150cc engine is rare to use. 

This is because 140 cc is the best choice for smaller lawns, and for larger lawns, 160 cc is far better in terms of price, capacity, and power. 

160cc and 190cc

If you want a high-powered engine, the most common engine outputs are 160cc and 190cc. 

Mostly, the engine that rates 160cc is 4.50 HP, and 190cc is 5.75 HP. 

But HP can be different according to the brand. For example, Honda lawnmower engines with a rating of 160cc have a power of 5.50 HP. 

So, the engine categorized with the cc does not always tally with the gross HP, and you need to assume each time. 

Factors that decrease horsepower in a lawnmower

There are a few factors that can decrease horsepower. Let’s list them out:

• Size and engine: Smaller lawnmowers are likely to have less horsepower than huge lawnmowers. For example, push lawnmowers has an engine output of 160cc, whereas riding lawnmowers have 560cc. 
• Damaged muffler: If the muffler is not properly attached to the engine block or is damaged, the lawnmower loses its horsepower. 
• Fuel: Using incorrect or damaged fuel directly affects the horsepower of the lawnmower and makes it slower.
• Unclean or broken air filter: If the air filter is not cleaned or it is broken, then the horsepower eventually decreases. 

Ways to increase the horsepower of a lawnmower’s engine

To increase this, you will need to fix those things which slow down the horsepower. 

Let’s discuss some ways which can improve the horsepower performance:

1. Check the rotating speed of the engine

First, detach the flywheel casing, which is placed over the engine. 

For removing, grab wrenches, unbolt the screws holding the flywheel casing and then take it out. 

Then look for the governor flap, which is beside the flywheel casing. 

Then inspect how quickly the engine rotates.

If it rotates too quickly, you will notice the governor flap extinguishes and slightly shuts the carburetor, slowing down the engine’s horsepower.

To fix this, unbolt the hooks and remove the spring that clutch the governor with the carburetor. 

Then, re-attach the flywheel casing back on the top of the engine. 

2. Inspect the muffler

The muffler needs to be appropriately fixed with the draining hole on the engine block. 

If it is not correctly fixed, the engine reduces horsepower when the muffler produces pressure. 

Try to attach the muffler properly to the engine block. 

If the muffler is defective, then immediately change it. 

The muffler doesn’t cost much, so you can easily change it whenever you want.

3. Use a higher-octane gas

Using a lower octane gas ignites at a slower speed, decreasing horsepower. Make sure you use a higher-octane gas. 

Use a gas that ranges at least more than 89 octanes to increase the horsepower gradually. 

Also read:

• Where To Get Gas For Lawn Mower?
• Will Mixed Gas Hurt A Lawn Mower? (5 Mistakes People Make)

4. Clean/replace the air or fuel filter 

Horsepower eventually slows down when the lawnmower receives unclean and polluted air or fuel in the gas tank. 

Try to inspect the air/fuel filter properly and clean it regularly to maintain it in proper condition. 

If the situation is bad and the filter can’t fix even after cleaning, then change it immediately with a new one. 

Also read:

• Can You Run A Lawn Mower Without An Air Filter?
• 16 Easy To Follow Steps To Clean Lawnmower Fuel Filter

How much horsepower does a lawnmower need for mowing?

The horsepower you will require in your lawnmower depends on 3 main things, i.e., size of the lawn, terrain type, and lawnmower’s type.

Let’s discuss all three factors in detail:-

Size

Choosing a lawnmower engine depends completely on the size of your lawn. 

If your lawn is large, you will need a lawnmower with high horsepower and vice versa. 

Let’s discuss the requirement of horsepower on different lawn sizes.

• For ½ and 1 acre lawn: Select a lawnmower ranging between 2.9 -9.0 HP with a cutting width of 40 inches. 
• For more than 1 acre and 2 acres of lawn: Select a lawnmower ranging between 10.0-14.0 HP with a cutting width of 40-44 inches.
• For more than 2 acres and 3 acres of lawns: Select a lawnmower ranging between 11.0-25.0 HP with a cutting width of 44-48 inches. 
• For 3 acres or more: Select a lawnmower between 19.0-25.0 HP with a cutting width of 48-54 inches. 

Keep this in mind, if the lawn is large, you should always select a lawnmower with higher horsepower as it will be more efficient and easy to mow. 

Terrain type

The horsepower you will need also depends on the terrain type. 

For example, a smaller lawn with a rough surface will require an engine with more horsepower. 

Now, let’s discuss the requirement of horsepower in different terrains. 

• For flat lawns: Select an average lawnmower ranging between 11.0-20.0 HP.
• For smaller lawns and rough terrain: Always select a self-propelled lawnmower ranging between 6.0-8.0 HP. 

Note: It’s better to avoid riding a lawnmower as it is recommended for larger lawns only.

• For larger lawns and rough terrain: Select a riding/tractor lawnmower between 20 HP and more. 
• For wet grass: Select a lawnmower ranging between 19.0-25.0 HP. 

Lawnmower’s type

If your lawnmower is different, you will require horsepower according to that. Let’s discuss the best HP for different mowers:

• For tractor lawnmowers (Rear engine riding lawnmower): Select a tractor lawnmower ranging between 11.0-20.0 HP.
• For surfer lawnmowers (Stand-on): Select lawnmowers ranging between 15.0-20.0 HP. 

Note: It should range between 25.0-37.0 HP for commercial use. 

• For zero-turn lawnmowers: Select a lawnmower ranging between 19.0-37 HP. 

This is the average horsepower you should select according to the different lawnmowers. 

How much horsepower is required for grass with high density?

If the grass in your lawn is too thick, you must keep it in a manageable condition. 

You will need a lawnmower with an engine unit of 25.0 HP for mowing high-density grass. 

The cutting width should be at least 42 inches, and you must modify the height from 6-13 inches, depending on the amount of cut you want to make. 

But if you have a big lawn with thick grass, then the lawnmower engine should be higher than 25.0 HP, and for efficient results, the cutting width should range between 52-72 inches.

Final words

Different lawnmowers have different horsepower. 

Normal push mower ranges from 4.5-5.0 HP, Self-propelled push mower ranges from 5.0-7.0 HP, riding lawnmower ranges from 12.5-25 HP, and surfer lawnmower ranges from 15-23 HP. 

Selecting the perfect lawnmower for your lawn depends completely on its size and terrain condition. 

Keep this in mind, lawnmowers with a higher horsepower can complete the mowing much faster. 

So the larger and uneven lawn will need high-capacity engines. 

While in the case of smaller lawns, the low-capacity engine is suitable.

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Reference: Lawn Mower Technology, Lawn Mower Safety, Lawn Mowing, Lawn Care, Mowing your lawn.