ABYC Diesel Practice Exam

Which of the following could cause the electric starter not to crank the engine?

1. A blown fuse

2. A run-down battery

3. An empty fuel tank

4. A faulty ignition switch

The correct answer is: A run-down battery

A run-down battery is a likely cause for the electric starter not to crank the engine because the starter relies on sufficient electrical current to engage and turn the engine over. When the battery is depleted, it does not provide the necessary voltage and amperage, hence preventing the starter motor from functioning. A battery that is low on charge may also struggle to sustain the load required to initiate the starting process. While factors like a blown fuse, a faulty ignition switch, or an empty fuel tank can disrupt the overall operation of the engine, they do not directly prevent the electric starter from engaging. A blown fuse would affect the electrical circuit related to starter operation, while a faulty ignition switch could fail to provide a start signal. An empty fuel tank, on the other hand, would prevent the engine from running once it is cranked, but does not directly affect the ability of the starter to turn the engine. This highlights the specific role that the battery plays in the starting process and why a depleted battery is the most direct cause of failure to crank the engine.