Aaron’s Engine Anatomy

Briggs and Stratton 8.75 hp motor

Background Briggs and Stratton is the worlds largest

manufacturer of air-cooled gasoline engines, producing an average of 11 million engines a year.

Piston the moving component that is contained

by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod.

Connecting Rod connects the piston to the crank or

crankshaft. Together with the crank, they form a simple mechanism that converts reciprocating motion into rotating motion.

Oil Splash

Splashes oil into the cylinder to keep it lubricated for the movement of the piston

Camshaft (Cam) The Cam controls the opening and

closing of poppet valves and is connected to a camshaft which rotates it

Crankshaft the part of an engine that translates

reciprocating linear piston motion into rotation. It is typically connected to a flywheel to reduce the pulsation characteristic of the four-stroke cycle, usually referred to as the crank

Poppet Valves Often just referred to as valves, they are

used to control the timing and quantity of gas or vapour flow into an engine. It consists of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem.

Cylinder Head Often referred to simply as the head, it

sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. The head also provides space for the passages that feed air and fuel to the cylinder, and that allow the exhaust to escape. The head can also be a place to mount the valves, spark plugs, and fuel injectors.

Engine Block an integrated structure comprising the

cylinder(s) of a reciprocating engine and often some or all of their associated surrounding structures (coolant passages, intake and exhaust passages and ports, and crankcase).

Spark Plug A device fro delivering electric current

from an ignition system to the combustion chamber of a spark ignition engine to ignite the compressed fuel/air mixture with an electric spark.

Governor A governor is a device used to measure

and regulate the speed of an engine.

Governor hook-up Controls how the governor is set up to

limit the speed of the enigine.

Fuel Tank Holds fuel until it is needed by the motor.

Carburetor a device that blends air and fuel for an

internal combustion engine. Also called the carb.

Fuel Hose Carries fuel from the fuel tank to the

carburetor.

Spark Plug Cap A "spark plug cap" or "boot" is hollow a

rubber elbow that helps prevent accidental electrical shock should the user come in contact with that area of a running engine.

Muffler Used to reduce the amount of noise

emitted by the exhaust of an internal combustion engine.

Exhaust Gasket A seal to prevent exhaust gas from

leaking.

Pull Cord Used to turn the starter cup which turns

the crank and flywheel to start the motor.

Flywheel A flywheel is a rotating mechanical device

that is used to store rotational energy. Some common uses of a flywheel include providing continuous energy when the energy source is discontinuous, delivering energy at rates beyond the ability of a continuous energy source. This is achieved by collecting energy in the flywheel over time and then releasing the energy quickly, at rates that exceed the abilities of the energy source, and controlling the orientation of a mechanical system.

Fan Used to keep the engine cool.

Gas Cap Used to keep the gas in the fuel tank.

Choke modifies the air pressure in the intake

manifold of an internal combustion engine and supplies a richer fuel mixture when starting the engine, hooked up to carb.

Air Filter a device composed of fibrous materials

which removes solid particulates such as dust, pollen, mold, and bacteria from the air to prevent abrasive particulate matter from entering the engine's cylinders, where it would cause mechanical wear and oil contamination.

Cylinder A cylinder is the central working part of a

reciprocating engine, the space in which a piston travels.

Air base Holds the air filter.

Crankcase Cover Covers the crankcase.

Oil Dipstick Indicates how much oil is in the engine.

Starter Cup