In small engines, the engines are small in both physical dimensions and power output, relative to larger automobile engines.
Their Power outputs are typically less than 11 kW (15 hp).
The smallest of all are used in handheld garden machineries, such as string trimmers and chainsaws.
Production cost is often a key consideration for small engines, resulting in relatively simple designs (compared with automotive engines, for example).
- The most common configuration is a single-cylinder engine that is air-cooled.
- The combustion cycle can be either two-stroke (which results in a lighter engine for given power output)] or four-stroke (which produce lower levels of exhaust gas emissions). The fuel is usually either petrol or diesel.
Electric starting, which has become more common over time, requires a more complex electrical system. These engines also require a starter motor, a battery to power it and an alternator to keep a battery charged.
Small engines can have the crankshaft oriented either horizontally or vertically, according to the intended application.
Vertical axis engines were originally developed for rotary lawnmowers, but the size of this large market has encouraged supply of cheap engines and they are now also used for other purposes such as generators
Motor Starter Varieties:
Four particular varieties of motor starters are: Across-The-Line, the Reversing Starter, the Multispeed Starter, and the Reduced Voltage Starter.
The six largest manufacturers of small engines for power equipment were Honda, Briggs & Stratton, Kohler, Generac, Subaru, and Kawasaki.