A lab 2-stroke petrol engine model is a small-scale model of a 2-stroke petrol engine commonly used in power tools, small vehicles, and recreational equipment such as scooters, mopeds, and chainsaws. The model is designed to demonstrate the principles of internal combustion engines, such as the intake, compression, combustion, and exhaust processes.

The model typically consists of a cylinder, piston, crankshaft, spark plug, and carburetor, and may also include a flywheel, exhaust pipe, and other accessories. When fuel is added to the carburetor and ignited by the spark plug, the resulting combustion produces a force that drives the piston and crankshaft, creating rotational motion.

The 2-stroke design of the engine means that the combustion process occurs twice per revolution of the crankshaft, resulting in a higher power-to-weight ratio compared to 4-stroke engines. The lab 2-stroke petrol engine model is commonly used in mechanical engineering and automotive technology courses to teach students about engine design, operation, and maintenance. It may also be used for demonstration purposes in science museums or educational outreach programs.