Which of the following is NOT a type of starter?

In this context, the term "starter" refers to the mechanisms used to initiate the operation of an engine. Each of the options listed represents a method for starting an engine except for one.

An electric starter is the common mechanism used in many engines, particularly in automobiles and smaller vessels. It utilizes electrical energy from a battery to crank the engine.

Hydraulic starters are used in larger engines, especially in marine applications, where hydraulic pressure is generated to initiate engine operation. This system is beneficial in heavy-duty applications where reliable starting under load is necessary.

Pneumatic starters utilize compressed air to start engines, often found in applications where electric power is not as readily accessible or where a rapid start is required. This type of starter can deliver significant torque quickly.

In contrast, an energy cell is not a recognized type of starter in the traditional sense. Instead, it may refer to a component or system associated with energy storage or supply, not specifically to starting engines. Therefore, it is not categorized alongside the types of starters mentioned. Recognizing these definitions helps clarify the purpose and functionality of each starter type in engine operations.