Lawn mower engines have a displacement of anywhere between 350ccm and 800ccm, which is the same engine size you can find in a full-size sports bike, and yet they still have a maximum speed of less than eight mph. Luckily, there are ways the speed can be improved, so here is how to make your lawn mower faster.
The easiest methods of making your lawn mower faster include installing a smaller driven pulley, installing bigger driven wheels, adjusting the throttle, removing the speed governor, and adjusting the hydrostatic transmission lever.
How To Make Your Lawn Mower Faster
Since all lawn mowers are different, the answer to how to make your lawn mower faster isn’t always the same. For example, adjusting the hydrostatic transmission lever won’t work on belt-driven mowers because they don’t have a hydrostatic transmission.
Furthermore, installing a bigger driven pulley won’t work on hydrostatic mowers because they don’t have belts and pulleys. That said, all lawn mowers have a speed governor, all allow for some extra throttle adjustment, and bigger wheels will increase the speed on all mowers universally.
Install Bigger Wheels and Tires
By installing bigger wheels, you are essentially changing the final drive ratio or shifting the transmission into overdrive. That’s also true on any type of vehicle, including cars which is why people install speedometer correction modules after getting larger wheels.
But ultimately, you will get a higher top speed but also slightly worse acceleration. Also, the speed increase depends on how much bigger the wheels are, but you are looking at about a 0.5 to 1 mph increase. Also, the bigger wheels will only make a difference if they or the driven axle, so on a rear-wheel drive mower, you want bigger wheels on the rear axle.
It’s also important to keep in mind that finding bigger wheels that fit the wheel hub on your mower might be a challenge. But your best chance of finding them is by looking up lawn mowers from the same manufacturer that get bigger wheels as standard and then try and find those on online marketplaces.
Besides the challenge of finding bigger wheels that are compatible, make sure they fit under the wheel arch and that they won’t rub on something on the inside of the wheel well. And lastly, used wheels for any type of mower will most likely be dirt cheap, which makes this an option you can’t go wrong with.
Install a Smaller Driven Pulley
A belt-driven lawn mower has two pulleys, one on the engine and one on the rear axle. You can substantially change the final drive ratio by installing a smaller driven pulley (the one on the axle), which is the best lawn mower pulley swap for speed. Also, you will get the same effect by installing a bigger drive pulley (the one on the engine), but replacing the one on the axle is much easier, and there are more options.
With a smaller driven pulley, you can increase the top speed to as much as the engine can handle, but a conservative number would be an extra 5 to 15 mph depending on the mower and pulley size. It’s also worth mentioning that the acceleration will suffer, and tall grass makes the engine stall much easier.
But if that’s not the kind of environment you are dealing with, then a smaller pulley is one of the best options on this list, plus a brand-new pulley is only around 15 bucks.
Adjust the Throttle Position
Almost all lawn mowers have a throttle adjustment lever, but that’s something you already know. But what you may not know is that the standard throttle lever can only open the throttle up to about 40%. To get around this, locate the carburetor, and near it, you will see a big metal levee with a spring attached to it; that’s the actual throttle.
You can even start the mower and move the lever around to see if you have found the correct one. If you have, engine speed will increase or decrease as you move it. After that, it’s up to you to figure out how to fabricate a manual throttle that you can operate while driving.
One way people do this is by tying up a piece of string to the throttle lever and routing it somewhere near the seat where they can reach it while operating the mower. However, keep in mind that over-revving the mower engine will increase the chances of engine failure.
Remove the Speed Governor
We already mentioned how lawn mower engines are relatively huge and don’t lack power, and now, the main reason they are so slow is the speed governor. A speed governor is an intentional way of limiting the speed or power output of a vehicle, be it a motorcycle, a lawn mower, or even a car. There are also numerous different methods and systems manufacturers use.
But the two main types of speed governors in lawn mowers are a special throttle assembly and a governor cross-shaft. The governor cross shaft closes the throttle once the engine speed exceeds the manufacturer-set RPM limit. In order to do that, the system uses a special throttle assembly to open and close the throttle.
By removing the governor lever that’s attached to the carburetor and the crankcase, you are overriding the system. That allows the engine to spin as fast as it can on fully open throttle giving you access to all the power it has. But keep in mind that this governor system is also responsible for the self-adjusting throttle.
That means you will have to install a fully functioning gas pedal. If you are working on large pieces of land, having to constantly hold the throttle open will get tiresome after a while, so that’s something to stay mindful of. But if you decide to go down that path, you can find complete lawn mower gas pedal kits on Amazon for around $100, but I’m sure there are cheaper ones too.
Adjust the Hydrostatic Transmission Lever
Here is how to make a hydrostatic lawn mower faster. By moving the hydrostatic transmission lever, you are changing the angle of hydraulic fluid passages. Essentially, a steeper positive angle gives you more forward speed, while a steeper negative angle gives you more reverse speed.
That makes it simple, if you want the mower to go faster, adjust the transmission linkage, so it goes more forward with the same amount of input. You can do that by accessing the linkage and finding the sliding adjustment bolt near the lever pivot point. Once you find it, loosen the bolt, adjust the lever, and tighten it back down.
However, keep in mind that after doing this, the lever won’t go as far back as it used to, so you will lose some reverse speed. And in extreme cases, you may lose reverse gear entirely, but it’s an adjustment game, so it doesn’t hurt to experiment with it.
Q: How fast can a lawn mower go?
How fast a lawn mower can go depends on the type, but most of them will do around 4-5 mph. And while some lawn mowers can do up to 14 mph, they likely won’t cut the grass properly at speeds of over 7-8 mph.
Q: What controls the speed of a lawn mower?
Several things control the speed of a lawn mower, like the speed governor, throttle setting, and in some cases, the transmission. Of the three, you can only influence the throttle and transmission setting to a certain extent, but to get the most out of a lawn mower, you will have to remove the speed governor.
Q: Why is my lawn mower not running fast enough?
Some of the reasons why your lawn mower isn’t running fast enough include a dirty air filter, a low throttle setting, a clogged blade well, or a clogged carburetor. You may also have worn-out blades if the mower only runs slow while cutting grass.
Q: How fast is the fastest lawn mower?
The fastest lawn mowers you can buy will reach 12 to 14 mph with factory settings. However, you can modify those lawn mowers to reach speeds of over 30 mph. And if you are asking how fast the fastest lawn mower ever is, it’s the Honda Mean Mower V2, and it can do 150.99 mph.
Q: How much faster is a 30-inch lawn mower?
In terms of moving speed, the blade length won’t affect it, which means that a 20-inch mower can be faster than a 30-inch mower. But if you are asking how much faster a 30-inch mower can cut grass on a certain piece of land, it’s about 30% quicker than an equivalent 20-inch mower.
Q: Does a lawn mower have horsepower?
Yes, like all internal combustion engines, lawn mowers have horsepower too. Depending on the type of lawn mower, it can have anywhere between 4.5 and over 30 horsepower. The latter is more likely to be found in riding lawn mowers.
Q: What is the best lawn mower setting?
The best lawn mower setting depends on the type of grass you have. For some types of grass, the best setting can be 1 inch, while for others, it can be as high as 3.5 inches. So, it’s best to first find out what type of grass you have and go from there.
In the end, there are plenty of ways how to make a mower faster, some of which are more difficult than others. Some of the easiest ways how to speed up a lawn mower are to replace the driven pulley or adjust the hydrostatic transmission lever.
Other methods include bigger wheels which won’t get you a significant speed increase, pus removing the speed governor, and adjusting the throttle position. But always keep in mind that exceeding a lawn mower factory set speed can be dangerous.