A tiller engine is typically the gasoline powered engine that powers the tiller or rototiller. The engines can run from less than one horsepower on the Mantis type tillers to more 10 horsepower on the larger Troy Bilt-type garden tillers. The tiller engine is typically mounted above the tiller's tines to place weight over them and promote better tilling. These are usually horizontally mounted engines; however, some of the larger tillers utilize vertical shaft engines.
In tillers such as the Mantis tiller, the tiller engine is a two-stroke engine, much like the engines used on string trimmers. These engines require the gasoline to be mixed with two-cycle oil in order to lubricate the engine. Larger garden tillers utilize a four-stroke tiller engine — the engines used on most lawn mowers, for example. These engines do not require the oil to be mixed with the gasoline and are somewhat easier to use and maintain.
Nearly all tiller engine cooling comes in the form of air cooling. Fins cast into the engines flywheel draw outside air into the engine's metal covering and direct it past the engine's cooling fins. This helps to dissipate the heat and draw it away from the tiller engine. This also allows the engine to operate without a radiator.
In some tillers, the tiller engine not only drives its tines, it also powers its drive wheels. This is possible through the use of a transmission. The engine is attached to the transmission, which directs some of the power to the drive wheels and some of the power to the tiller tines or tiller attachment. The engine operates at a given speed and the transmission gears direct the proper speed to different areas of the tiller through a series of gears or belts and pulleys.
The vast majority of tiller engines use a pull rope to start them; however, some of the high-end models use a battery and an electrical starter much like an automobile. The pull-start versions are the most common and are fairly easy to start. The tiller engine does not have a very high compression engine, so it is able to be pulled over by most people.
The gasoline-powered tiller has made gardening much more enjoyable than times when a shovel and a hoe were the only choices to maintaining a garden. With the introduction of the micro-tiller, such as the Mantis, even flower beds are now easy to maintain. The tiller engine has earned its spot in the hearts of gardeners all around the world.