Recoil Start

Recoil start (also called manual start, pull start, or zip start) refers to a method of starting an internal combustion engine, usually on small machines, such as lawn mowers, chainsaws, ultralight aircraft and portable engine-generators. Recoil start is also used on some small vehicles such as small go-karts, minibikes, and small ATVs.

The starter consists of a rope with a grip at the end, coiled around an end of the crankshaft. When the rope's grip is pulled, the rope uncoils around the end of the crankshaft, spinning it to crank the engine. After the rope is pulled, the flywheel keeps spinning and the engine starts. If the grip is not returned gently, it can damage the starter by the rope getting tangled in the mechanism. The rope is not directly connected to the crankshaft itself, but to reel that is connected the crank by a racheting mechanism. When the rope is pulled, the rachet engages the crankshaft and forces it to spin as well. Once the engine starts, the rachet mechanism allows the crankshaft to keep spinning, while a coil spring inside the reel mechanism reverses its direction and recoils the rope (hence "recoil starter"). If the reel were directly connected to the crank, once the rope reached its end, the spinning crankshaft would keep turning the reel, which would violently recoil the rope in the opposite direction until it reached its end, where it would likely jam and stall the engine.

There is an older, simpler version of pull starter that has a reel directly connected to the crankshaft, and a rope that is not connected to the reel. The rope is wound around the reel and pulled, starting the engine, but once the end of the pull is reached, it comes free, leaving a loose rope in the persons hand. If the engine fails to start on the first pull, the operator has to re-wind it by hand. This is also done when the engine is shut down to prepare it for the next start.

Aircraft piston engine components, systems and terminology

Piston engines

Mechanical components	Camshaft Connecting rod Crankpin Crankshaft Cylinder Cylinder head Gudgeon pin Hydraulic tappet Main bearing Obturator ring Oil pump Piston Piston ring Poppet valve Pushrod Rocker arm Sleeve valve Tappet

Electrical components	Alternator Capacitor discharge ignition Dual ignition Generator Electronic fuel injection Ignition system Magneto Spark plug Starter motor

Terminology	Air-cooled Aircraft engine starting Bore Compression ratio Dead centre Engine displacement Four-stroke engine Horsepower Ignition timing Manifold pressure Mean effective pressure Naturally-aspirated Monosoupape Overhead camshaft Overhead valve Rotary engine Shock-cooling Stroke Time between overhaul Two-stroke engine Valve timing Volumetric efficiency

Propellers

Components	Propeller speed reduction unit Propeller governor Spinner

Terminology	Autofeather Blade pitch Contra-rotating Constant speed Counter-rotating Scimitar propeller Single-blade propeller Variable pitch

Engine instruments

Tachometer
Hobbs meter
Annunciator panel
EFIS
EICAS
Flight data recorder
Glass cockpit

Engine controls

Carburetor heat
Throttle

Fuel and induction
system

Avgas
Carburetor
Fuel injection
Gascolator
Inlet manifold
Intercooler
Pressure carburetor
Supercharger
Turbocharger

Other systems

Auxiliary power unit
Coffman starter
Hydraulic system
Ice protection system
Recoil start

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