käsikäivitussüsteem

Käsikäivitussüsteem is an Estonian term that translates to "hand-start system" or "manual starter system" in English. It refers to a method of starting an engine without the use of an electric starter motor or other automated means. Historically, this was the primary method for starting many types of internal combustion engines.

The most common form of a käsikäivitussüsteem involves a crank handle. This handle is inserted into a corresponding socket on the front of the engine, typically connected to the crankshaft. The operator then manually rotates the crank handle, which in turn rotates the engine's crankshaft and pistons. This action draws the fuel-air mixture into the cylinders, compresses it, and when the ignition system fires, the engine begins to run under its own power.

Another type of käsikäivitussüsteem, often found on smaller engines like those in lawnmowers or chainsaws, is a pull-cord mechanism. A rope is attached to a flywheel or a similar rotating component of the engine. When the operator pulls the rope sharply, it engages a mechanism that rapidly spins the engine's crankshaft, initiating the combustion cycle.

While electric starter motors have become standard on most vehicles and larger machinery due to their convenience and ease of use, käsikäivitussüsteem still finds application in certain contexts. These include smaller engines where the cost and complexity of an electric starter are not justified, emergency backup systems, and in some vintage or specialized equipment where a manual starting method is part of the design or restoration. The simplicity and robustness of a hand-start system are often seen as advantages in environments where electrical systems might be prone to failure or difficult to maintain.