After closing the main battery switch, what is the next step in the engine startup procedure?

After closing the main battery switch, what is the next step in the engine startup procedure?

• A. Prime the engine as indicated on the badge plate.
• B. Crank the engine immediately.
• C. Check oil level.
• D. Engage the air brake.

Answer: (A)

Priming the engine to purge air and establish fuel pressure before you crank is the step being tested. When you close the main battery switch, the fuel system can still have air in the lines, so the engine won’t start reliably until fuel is pushed through to the pump and injectors. The badge plate tells the exact priming procedure (how many priming strokes or cycles, and any throttle position) to use, ensuring fuel is ready to deliver to the cylinders as soon as you begin cranking. If you skip priming and go straight to cranking, you risk cranking with little or no fuel pressure, which leads to hard starting or no start and can waste battery power. The other options aren’t relevant at this moment—oil level checks are a broader prestart task, and engaging the air brake has no bearing on starting.

Priming the engine to purge air and establish fuel pressure before you crank is the step being tested. When you close the main battery switch, the fuel system can still have air in the lines, so the engine won’t start reliably until fuel is pushed through to the pump and injectors. The badge plate tells the exact priming procedure (how many priming strokes or cycles, and any throttle position) to use, ensuring fuel is ready to deliver to the cylinders as soon as you begin cranking. If you skip priming and go straight to cranking, you risk cranking with little or no fuel pressure, which leads to hard starting or no start and can waste battery power. The other options aren’t relevant at this moment—oil level checks are a broader prestart task, and engaging the air brake has no bearing on starting.