Increase Lawn Mower Horsepower? Here’s How To Do It.

As an avid fan of knights, court intrigue and medieval kingdoms, I can attest to the sentiment that “power is power”. Who doesn’t love a good old muscle flex, and especially of the motorized variety? Instead of muscle cars, I am talking about lawn mowers. Can you increase your lawn mower’s Horsepower?

To increase your lawn mower horsepower it is important to use higher octane gas. You can also remove the governor flap that is designed to throttle engine horsepower. For older mowers it also helps to clean or replace dirty air filters and replace worn mufflers.

Nope, we’re not talking about hot rods, we’re talking about lawnmowers! Our focus today is on the optimum power output levels for various mowing scenarios and conditions. We will also get our hands dirty with a DIY how-to guide on how to crank out even more horses from your mower’s stable. Giddy up!


What Is A Good Horsepower For A Lawn Mower?

Much like cars, lawnmower power output is often measured in horsepower. Also, like vehicles, this output varies from mower to mower. Various factors influence the kind of output a manufacturer assigns to a machine.

A good horsepower for a push mower and one-half acre of grass is 3.5 to 4 horsepower. For just under an acre, a 7 horsepower self propelled mower will do well. If the job is 2 to 3 acres, a rider with 15 HP is an adequate pick. For more acreage, over 20 HP professional mowers are better.

So, what makes one mower require one level of power and another require more horses?

More Mower Size Requires More Horsepower

The size of the lawnmower is one of the main factors. More specifically, the weight of the mower. This is especially true for self-propelled and riding mowers that have to haul their masses around. The less a mower weighs, the fewer horses it needs to get the job done.

Load Capacity Takes More Horses

Another factor closely related to weight is load capacity. This mostly applies to lawn tractors and zero-turns which have to accommodate a rider and, sometimes, peripheral implements. All this added weight requires more horsepower from the engine. 

Commercial Versus Residential HP

A further consideration is the lawnmower’s intended purpose. Private use lawnmowers for homes typically have lower power outputs than commercial mowers, which are equipped to be ready for any task. 

Some manufacturers also classify their mowers by the total area they can cover. You can expect machines classified as 5-acre mowers to have more power than those with lower area ranges.

Now that we’ve seen the considerations manufacturers make, let’s examine how customers can determine the best power output for their lawn care needs.

Need Mower Horsepower? How Do You Choose?

“Good” power output is subjective and dependent on various needs. Will your prospective mower be used privately on your property or as part of a landscaping business? What kind of grass do you have? What is the layout of your yard like?

You need mower horsepower that relates to the job intended and the weight of the mower designed to do it. Push mowers need the least HP, with self propelled versions needing slightly more. Residential riding mowers cutting larger yards need more horsepower, but not as much as commercial machines.

These are the kinds of things you need to think about before you go and purchase a machine that is either too over or underpowered for the job you want it to tackle. 

Yard Size And How Much Mower Horsepower Is Needed.

It stands to reason that tiny yards would need smaller and less powerful equipment. There just needs to be a simple delineation made for those that are not as experienced or have not considered it in a while. Here is a chart that can help with an explanation to follow.

Lawn SizeMower TypeRecommended HP
1/2 AcrePush Mower2-5 Horsepower
1 AcreSelf Propelled Push Mower5-7 Horsepower
2-3 AcresResidential Riding Mower12-20 Horsepower
3+ AcresProfessional Mower25-30 Horsepower

Typically, yards smaller than ½ an acre can be covered using a simple power push mower with 2-5 horsepower. A yard with up to an acre can be tended to by a self-propelled walk behind. On average, self-propelled mowers have power ranges of 5-7 horsepower. Some self-propelled mowers can even go beyond 10 horsepower.

When it comes to areas larger than an acre, you’re better off with a riding mower. The term “riding mower” includes lawn tractors and zero-turn mowers. Of course, not all riding mowers are created equal. These machines range from 12 to 20 horsepower on average, although brands like John Deere and Toro have several models with 25+ horses.

Terrain And Grass Condition Require Certain Lawn Mower HP

Once you’ve factored in your work area size, you should also consider the terrain. If the ground is uneven, which requires a lot of uphill movement from your self-propelled or riding mower, you will need more horsepower than you would on flat land. 

The same goes for dense grasses. Tough grasses like Bermudagrass require more power to cut because they can grow to be so thick. While grass density is a relatively minor factor when compared to yard size and gradient, a combination of the three can hinder an underpowered mower.

The length of your grass is just as important as the density. If you have fast-growing grass, you may have to go over several cutting lanes more than once. This also requires a mower with high power output to save time.

Wet Conditions And Horsepower

Your local climate and season of the year are additional considerations. Moisture and rainfall are your primary concerns here. If you live in an area that receives a lot of rain, you will have to tackle wet grass frequently. 

The danger with wet grass is that the moisture invites fungi and other disease-causing organisms that can hurt the lawn. To avoid this, you must ensure that the grass is cut cleanly, not torn.

This can only be done with a combination of sharp mower blades and an adequately powered engine. A mower with at least 15 horsepower should do the trick.

If you like this article, I recommend you try out some of my other articles here…

How To Increase Lawn Mower Horsepower

One of the many reasons we love lawnmowers is the ability to make DIY tweaks to them. Most manufacturers give their customers room to make repairs and even upgrades, something we truly appreciate. 

Let’s take a look at how you can increase power output to boost your mower’s performance. 

Mower Engine Exact Power Output

The first thing to note is that with most mowers, the advertised horsepower value is not the engine’s exact power output. Manufacturers tend to hold back a few horses for optimized engine performance, fuel efficiency, and longevity. 

Luckily, you can “hack” the system to allow the engine to reach max capacity. However, it is best to do this to a machine that is not under warranty so you can minimize potential headaches in the future.

1- Remove Governor Flap

One power-boosting approach is to remove the governor flap, which is located under the flywheel housing. The governor flap restricts engine power when the engine’s RPM gets too high. The flap is usually bolted next to the flywheel. Use wrenches to detach the flywheel housing and then remove the flap. 

2- High Octane Gas

Another approach is to simply switch to high-octane gasoline. Super-premium fuel burns at a much faster rate than regular gas or ethanol blends, which will increase the engine’s power output. 

While the above steps are for boosting a fully functional mower, there are also ways to restore lost horsepower if you notice a significant drop in performance.

3- Replace Mower Air Filter

One way is to check and replace the lawnmower’s air filter. This filter accumulates dirt and debris over time, which limits airflow and, ultimately power output. Air filters should be replaced at every service.

You can compare the prices of many types and brands of mower air filters at this link to Amazon.

4- Replace Old Mufflers

A damaged muffler is another silent (pun intended) horsepower killer. If your mower is not performing as it should, you should carry out an inspection and see if the muffler is cracked or damaged. 

Under normal circumstances, the muffler is supposed to help the engine retain pressure, which maintains appropriate power output. If the muffler has holes in it, or if it is detached from the main engine block, this pressure escapes, which makes the lawnmower lose power.

If the muffler is detached, simply screw it in properly and ensure it stays in place. If it is damaged, you must replace it with a new one.

The Final Touches On Increasing Lawn Mower Horsepower…

Getting a mower that has too little horsepower can cause a mowing job to take much longer at the least and damage the machine in a worse case scenario. It can actually be an important choice to make for efficiency and cost effectiveness, as well as to satisfy the need some of us have to hear the “power” of the revved up mower engine.

It is not necessary to get the most horsepower on the market for most lawn care needs. If it is simply something you want to do for preference, then knock yourself out. Yet, if it is the most bang for the buck you have to spend then hopefully the information here can help you make the right decision for your jobs at hand.

To see more articles like this one, here are some of my others that I recommend…


Mathew Booe

Mathew has worked in landscaping professionally for over 10 years. He is a grandpa and frequently interviews other experienced landscapers and lawn care experts who are also grandpas for these articles.

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