What controls the speed of a lawn mower?

All lawn mowers will come with a type of speed control called a throttle control lever. This lever, which is essentially a plastic slider on the handlebar, will be attached to the engine throttle via a cable hook up. As you move the slider back and forth, the cable mechanically relays these exact same movements to the engine throttle which opens or closes the carburetor, allowing either a little gas into the motor, making it run slower, or a lot of gas which will make it run faster. And this is all done with a throttle control slider.

Start your lawn mower. This is where you will first use the throttle control slider. Push the slider on the handlebar all the way forward. This action will engage the choke which will allow easy cold starting.

• All lawn mowers will come with a type of speed control called a throttle control lever.
  
• This lever, which is essentially a plastic slider on the handlebar, will be attached to the engine throttle via a cable hook up.

Pull all the way back on the throttle controller once the motor is running. This will make the engine idle. Most slide controls have some sort of visual aid icon printed on them to signify the position where the throttle control would be positioned for a slow running engine-usually pictured as a turtle-and where it would be positioned for a fast running engine-usually pictured as a rabbit. So pulling all the way back on the throttle control would line up the turtle with the lever and therefore, a motor running at idle..

Slowly advance the throttle controller. As it slides forward, you will hear the motor begin to pick up speed, and when you get to the end of the slide, the motor will be running at full tilt. This is where you want to begin cutting grass.

• Pull all the way back on the throttle controller once the motor is running.
  
• So pulling all the way back on the throttle control would line up the turtle with the lever and therefore, a motor running at idle..
  
• Slowly advance the throttle controller.

When finished cutting grass, pull the throttle control all the way back to the idle position, and turn off the lawn mower.

In almost every cutting grass job, you will be running your lawn mower at full speed, so the throttle control slider will be pushed all the way forward. Why? Because the motor is hooked up to the blade driveshaft directly, so the faster the motor runs, the faster the blades turn, and the cleaner the cut you will get when you are mowing the lawn.

Mowing the lawn isn’t everyone’s favorite chore, even if the mower is in great shape. Getting the cut right the first time is important, because finding out you have to go back and cut the entire lawn again -- or worse, that you cut too much -- can ruin your day. The speed the mower runs at affects the health of the grass and the efficient completion of the task.

Not Too Fast

1. The speed at which you push or drive the mower can make a big difference to your lawn. Mowing too quickly -- either pushing too fast or accelerating to too high a speed -- can tear grass blades, resulting in a rather scraggly lawn. The torn grass tips can also turn brown. Jack’s Small Engines notes that mowing too fast can leave streaks of taller grass behind too. In addition to ruining your lawn, pushing a mower too fast can make the mower bounce, leaving nearly bald patches. This is called scalping, which refers to too-close cuts on small mounds or hills in the lawn. It can also occur when the mower hits the ground after bouncing.

Some Speed Is Good

1. The cure is usually to slow down and give the blades time to cut the grass, rather than running across your lawn in hopes of finishing quickly. However, that does not mean you can slow to a crawl. Moving too slowly can let grass clippings form clogs that make the mower difficult to use. Agway advises mowing at a “brisk” pace -- so you’ll have to do some experimenting to see what speed works best for the mower you’re using. Mow for a bit and inspect the results, and adjust how fast you’re going as a result.

It Could Be the Mower

1. In addition to your speed, the mower’s engine speed is an issue. In this case, the engine speed has to be fast. Jack’s Small Engines advises mowing at full throttle to avoid leaving streaks and patches of uncut grass. The throttle itself, inside the engine, will actually open and close to compensate for the change in load as the mower moves over different types of ground, such as hills and valleys. The part that controls this is called the governor, and you can manually adjust it. This isn’t a one-size-fits-all procedure and can vary by mower model, so you have to look at your specific model's manual for the right procedure. In general, though, you would disconnect the spark plug, and after inspecting the springs and general state of the governor, you’d adjust the governor shaft and a bolt.

Other Considerations

1. If you think your mower speed is fine and you don’t want to open up the engine to look at the governor if you don’t have to, check the blades, deck and general condition of the mower first when hunting down the cause of poor mowing results. Operator error is often behind lawn-mowing problems, but you might also have dull blades, an uneven deck, a damaged spindle or more.

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