Engine Starter Cranking Limits for the first engine are?

• A. 90 seconds ON followed by 10 seconds OFF
• B. 60 seconds ON followed by 15 seconds OFF
• C. 120 seconds ON followed by 20 seconds OFF
• D. 90 seconds ON followed by 0 seconds OFF

Answer: (A)

Starting the engine with the starter draws a large amount of current and generates a lot of heat in the starter motor and related electrical system. To protect the starter from overheating and to avoid battery and wiring stress, a duty cycle is used during cranking. For the first engine, the approved sequence allows up to 90 seconds of continuous cranking, then requires a 10-second pause to cool before another attempt. This cooling interval helps dissipate heat, reduces the risk of starter damage, and improves the chance of a successful start by stabilizing electrical conditions. Other schedules that push longer continuous cranking or have no rest don’t give the starter enough cooldown time, increasing the chances of overheating and failure to start.