If you're like most people, when you hear horsepower, you think cars, not lawn and garden care. Of course, if you're looking for a utility tractor, you may actually begin to think about actual horses. But when you compare the horsepower rating of car engines to the horsepower ratings of tractors, you'll see there's a big difference. You may wonder, how can something with just 50 horsepower get anything done?
Horsepower isn't quite as important to tractors as it is to cars. Horsepower is what keeps a vehicle moving once it's up to speed. However, if you remember your physics, an object in motion wants to stay in motion -- it doesn't really take much effort to keep the motion up.
On the other had, an object at rest wants to stay at rest. And when that object is a tractor pulling a heavy load, it will take a lot of power to initially get it moving. That's where torque comes in. Torque is the amount of force an engine generates to get a vehicle moving. Of course, torque isn't always used to get a tractor moving. It also refers to the engine's rotational power, and that's what powers attachments. When shopping for a tractor for your home and garden, pay attention to the torque rating. The more torque an engine has, the better it is at giving power to attachments at low engine speeds. That means less engine wear and tear (since you won't have to rev the engine to get your work done), less fuel will be used and it'll be less likely to stall, too. In short, having more engine torque means the tractor can do its work more efficiently.
Because tractor engines have different uses than car engines, diesel engines are more common. Diesel engines tend to make more torque than gasoline engines, and they tend to be more durable.